We get this question almost daily from couples we see in our sex therapy practice.  Couples want to know if what they are doing is “normal”.  Check out this recent article in the New York Post: How Many Times You Should Be Having Sex Each Week.   It states, according to studies, happy couples have sex 3-4 times a week.  
 
Every couple is different and there are many variables that can impact how often couples have sex. We agree with Couples Psychotherapist and Certified Sex Therapist, Sari Cooper:
 

 
Some couples have uneven sexual desire:  one partner wants sex more often and the other less often. And believe it or not, there are some happy couples out there who are in sexless marriages which means they are having sex less than 10 times a year.  But the amount of sex (or lack of sex) they are having works for them.  That’s their normal.
 
Thus, the bottom line is couples need to talk about how often they want to have sex and negiotate what’s “normal” for them.