Hi, I'd like to help you with your question.
It depends very much on the couple. There is no normal when it comes to frequency of sex for a married couple. The numbers vary tremendously. Much of it depends on factors such as children, stress, job issues, ability of the couple to get along, drug and alcohol problems, and other issues. Also, some couples feel one time a week is enough, others feel once a month is good enough.
What often occurs is that one partner will want sex more often than the other. This is where the conflicts come in. If the couple cannot reach a compromise, then therapy is recommended to help them work it out.
I hope this helps you,Kate