Very simply and with 100% certainty, no.

There are a few exceptions that make it an acceptable MOMENT for your child or children to be in the parental bed.
For example, if your child is sick. Both you and your child will feel more secure, especially if you are having to check a fever or other symptoms. Also, if there's been a traumatic event, your child may need more 'snuggle time' than usual.

A healthy family has healthy boundaries.

One must also take into account the time that should be shared exclusively between partners. All day long, you and your husband deal with the demands of the balancing act of children and careers. There is no personal or intimate time during all this chaos. The only opportunity that most couples have is at the end of the day. Only then is alone time available. It is this time that keeps communication open and allows for intimacy. A healthy relationship depends on this time. If your marriage does not have this balance, your family is in danger. Your marriage is the foundation your entire family is built upon. Disturb or weaken that foundation and you're in trouble.

Another issue with a child sleeping in the same bed with their parents is the average male will have an erection every 90 minutes. While a father may in no way intend to 'show' this side of himself to their child it will eventually happen. Psychological issues may develop within the child when sexual identity is developing.

If a divorce occurs and a child is put in the marital bed with a parent a child is then left to deal with the emotional issues that they are not equipped to deal with. For example, the emotional needs that was once filled by a spouse will turn to extra nurturing and attention on a child. This attention and nurturing will be too much. Once a parent remarries or brings another adult into the bed, chances are the child will then be put back into their own bedroom. What then? Feelings of competition and inadequacy will develop along with jealousy and displacement.

If your child needs reassurance I suggest going into your child's room at night and if need be, wait until they fall asleep and then go back to your own bed. Eventually, a routine will develop and your child will feel independent enough to sleep on their own.

Remember, a child sleeping on their own is important for their development. You want a child who is independent. This is an important step in making this happen.

A young child is physically in danger when it comes to co-sleeping. I'll not touch that issue as we're discussing a 4 year old, but wanted to add that in the event a parent with a younger child is reading this. I will say that recently a friend of mine's 14 month old died due to co-sleeping. Please research the dangers of co-sleeping.