I don't think there is a set limit to how often a married couple should have sex. Sometime we tend to think that sex should happen more once married but it is not always so. A couple is made up of two individuals with varying sex drive. One may have a high libido and the other a low one or both may have high or low libido. Thus affects how often sex is demanded and carried out by one or both partners. Again, some couples have very busy schedule and so hardly find time for sex as they are usually tired at the close of day,

The answer to this question depends on the couple and their definition of what is normal to them. They can have sex couple of times a week or even just once a week so long they are happy with that routine. The quantity of sex sometimes is determined by the quality of sex. If the quality is low then the quantity will also be low. In this case there is an underlying problem and such both should communicate and try to find ways of boosting their sexual life. Seeing a sex therapists can also help such couples.

All in all there is really no normal when it comes to the number of sex couples should have. It's a matter of whatever rocks your boat. Some couples keep a sex timetable. If that works for you, you can try it out. If you are wondering how many times the other couples are having sex then perhaps your sex life has issues that needs to be fixed and yes it can be fixed.