That depends why you can't sleep together.

I think it's undeniable that sex is an integral part of any relationship. However if you married because you love one another, and you still do, I think you owe it to that love to try and work what ever it is out.

The only case where I would say not being able to sleep together warrants a divorce is when it's inspired by a lack of love and attraction for one another.

Why can't you sleep together anymore?

Is it because?

1. he is sexually inept? if so, consider whether that is really important to you or not.
2. Do you two not love each other anymore? If so, yes, go for the divorce!
3. Does he snore too loudly? If so, it'd be awfully mean for you to try to get a divorce.
4. Does he or do you have insomnia? if so, then it is time to see a psychologist!

Indeed, like others say, it all depends on why you can't sleep together any more. If the reason is snoring, you don't have to think to divorce :)

Instead if you don't love your significant one any more then, you should try to talk to him, try to make him understand why you feel left alone in the relationship and together make things change.

But sleeping in separate bedrooms can have a positive effect on a relationship: the need to attract the other on the other side of the wall, creating special situations that look like the first days you met or would look like "forbidden" ones, etc.

A friend of mine never loved her husband as much as she did when they stopped sleeping with each other firstly because he moved too much in their bed and secondly because when he finally fell asleep, he started snoring so high that my friend was unable to sleep. But they took advantage of the situation to discover each other.

The first thing to analyze is why you don't want to sleep together then, making decision on what to do, whether talking to him, getting separate, see a psychologist for couples or any other alternative.

Hope this helps a bit.

Since your user name is Sleepless, I'll assume that snoring or some other sleep disorder (restless leg, insomnia)is the issue.
This is not uncommon. I, myself plan to have some rhinoplasty done in the near future, to open up my airways.
Snoring runs in the family. And there are serious health benefits to consider when deciding on such an operation. Most importantly better oxygen intake while sleeping than breathing through my mouth, which brings up apnea issues and straining of the heart.

In your case I've included an excerpt and link to one of many articles available to say that you are not alone,
well... at least when you're awake, along with suggestions on how to make it work, and possible solutions to get you two back together.

Happy Cuddling

Excerpt from: Sleeping Single in a Double Bed by Jeanie Lerche Davis
http://www.webmd.com/sex-relationships/guide/sleeping-apart

...Turns out, lots of couples are sleeping apart. A 2005 National Sleep Foundation survey found that 31% of couples are changing their sleep habits because of a mate's sleep problems:

23% sleep in separate beds, bedrooms, or with someone on the couch.
8% alter their sleep schedules.
7% wear earplugs or a sleep mask to ensure that they get a good night's sleep.
Also, 38% said that their partner's sleep disorder has caused problems in their relationship; 27% reported that their intimate relationship has been affected by sleepiness. Another interesting tidbit: 34% of women said they required eight hours or more of sleep, compared with 18% of men.

The Sleep Myth
"There's nothing at all wrong with sleeping apart," Williams says. "But it goes against everyone's myth that we should all sleep cuddled up together -- that's our ideal vision. And most people want to get back to that ideal."

"Sleep is about sleeping," says Louanne Cole Weston, PhD, a sex therapist and author of WebMD's Sex Matters message board. "If you're not getting sleep next to your mate, you're not going to be happy, pleasant, or easy to get along with. And if there's resentment because someone isn't getting enough sleep, there's not likely to be sexual intimacy." ...

No, but it’s definitely time to sit down and talk. If you and your partner have not been intimate for a while chances are this incidence has not gone unnoticed by your partner. Your number one job now is to find out precisely what is going on in both of your lives that prevents you from being intimate with each other. Ask your partner to sit with you and try to figure out what has changed in your lives. How long has it been that you were intimate, or how long since you both enjoyed each other’s company while being intimate? What is different now and what has changed since that time? Has your spouse recently changed jobs and has less time for you? Have you taken on additional duties that cause you to be too distracted or tired to consider a romantic encounter after a stressful day. Asking yourselves these types of questions would help you determine whether recent activity changes have taken up personal time and caused you and your spouse to be less focused on each other. If no such changes have truly occurred in your lives, you must then consider other alternatives, and ask yourselves truthfully whether either of your feelings toward the other partner have changed in any way. Has either partner lately felt resentful or angry towards the other? Has either of you started feeling differently about your relationship, or is your love still as strong as it has always been? If feelings have changed for you or/and your spouse, try to find out why. What was the source for these different feelings that now do not allow you both to be intimate anymore? Only by being completely honest with each other (even if it hurts to find out the truth) can both of you understand what is happening to your love life and then decide what you would like to do differently in the future. Contemplating immediate divorce before all the facts are out on the table may be an irrational and unnecessary step to take. Divorce is a very common occurrence in family relationships and many couples often think that as soon as something goes wrong in their relationship, divorce must be the answer. Don’t fall victim to this fallacy. Obviously you married your partner for a reason. As long as both of you still have feelings for each other and no third (or fourth) person is involved, you have all the chance in the world the try an iron out your intimacy problems. Honesty is key, as is keeping an open channel of communication with your partner. If you both still feel strongly for each other but have just neglected your sex life lately (due to whatever reasons), make immediate plans to spend some quality time together, just you and your partner. That means that if you have children, make arrangements to have them looked after and try to get away from the everyday stresses (bills, jobs, household, etc) that may keep you both from enjoying each other’s company to the fullest. Sometimes, especially if you have been together for a longer time, the relationship can turn monotone, and partners can become bored with each other and seriously question the value of their being together. The trick is to add spice to your relationship every now and then that helps you remind yourselves of why you fell in love with each other in the first place.

When you say "can't sleep together", do you mean that you can't sleep in the same bed, or do you mean that you can't stand having sex with each other any more?

If it's because the sex is still great, but you can't sleep in the same bed, then set up separate rooms and pass out in the same bed together only on those special occasions.

Having your own bedroom is a time honored tradition going back into prehistory and going all the way up to the highest levels of royal nobility even today, plus, don't forget... just like how in north America the tried-and-true discipline of wearing school uniforms was dropped because the continent went through times when people were too poor to afford school uniforms, such that it was drop the school uniform requirement or stop going to school, so also for thousands of years and all over the world it's been normal for men and women to sleep together or apart however they want, such that it's only been in times of poverty and privation that couples would *have* to sleep together (and have sex while kids were sleeping on the other side of the room... do you think *that* old tradition required sustenance... or was it turfed the instant more amicable sleeping arrangements could be organized?)

I've dealt with it first hand, because for a time I was with a woman who snored like mount Vesuvius, and although we'd have plenty of fun together, usually in her room but sometimes mine, once the party was over I would move or I just wasn't going to get any sleep (if she passed out in my room then I'd move to her room and wake up in the morning there, which bothered her more than the other way around, which is how the pattern came to be that we partied in her room).

She was cool with all of it, because she'd been through two previous relationships that had split because of her snoring. The previous guys couldn't or wouldn't accommodate (which I thought was weird, because I liked being able to wake up to a timer-controlled TV tuned to the morning world news and a coffee pot already percolating, neither of which she would tolerate in her room, plus I like dark-blue walls and wasn't getting blinded by pink, and I could find my pants where I left them...).

However, if by "can't sleep together" you mean you cant stand having sex with each other, then that phase of your relationship is over and the only thing stopping you from following your natural paths apart would be if you've got kids and/or if you're financially bound up together.

Already a billion books will have been written about how to handle a separation when kids and/or combined finances are involved, and the reason there are so many books is because there are as many solutions as there are permutations and combinations of couples that are or ever have been on this planet, but I want to tell about one in particular that was interesting...

Not to be copied... but just to show an example of how wide-open the possibilities can be for sorting things out when two people are not a natural couple anymore yet are still tied together by finances and kids, if people will just be rational and realistic and use their minds and imaginations to work *with* their hearts to find a solution.

In their case, they had three kids (two boys and a girl) and they were each professionally employed and able to be financially independent... just not as well off as when they were able to combine income to take advantage of the economies of scale.

In their city, there were lots of duplexes in okay neighborhoods, so they bought one, and knocked out the wall in the basement.

The basement was converted into a semi-suit with three bedrooms for the kids, two bathrooms, and a general living area. The lock system was where his key would only work on his doors and on the door into the basement, hers would only work on her doors and the door into the basement, and the kids keys would open up everything.

The kids could hang out in the space downstairs, or they could choose to go upstairs into either the mother or the father's part, although they had to leave if they didn't really need the parent and the parent had a good reason for them to leave.

The only part about it that seemed a bit odd was that the kids never got their own entrance. They always had to come and go through one or the other parent's half of the duplex.

Oh yeah... and the backyard was split by a juniper hedge 12 feet high.

They got along... he continued with his career in one of the colleges, and she continued with her career in one of the middle schools, and the kids grew up okay.

They worked out a protocol for sharing meals with the kids... knowing who would eat where when what was being served, and I think the daily rounds of everyone figuring out which kid was going to eat where and therefor how much should be made is how they maintained independence while still functioning as some sort of community and not just two ex's forced to split costs and the burdens of responsibilities.

When all the kids were gone, they sold the place. The new owner did some renovating, choosing to lived in one of the upstairs halves, and then he rented the other upstairs half and area downstairs as a suite, and everyone was okay.

By not ripping each other apart in a divorce, the couple ended up making a profit on the place they raised the kids in, even though they were separated.

I'm not offering that as any kind of blue-print. I'm just showing it as an example of how, if you're just not compatible as mates anymore, and you're not enemies, but you're bound by kids and shared finances, then there *are* ways to reorganize things for each to be independent again without chucking responsibility... if people can think with an open, rational, creative and fair mind.