Healthy marriage with barely any sex.

Ally

I've talked to a few of my friends about this and only my mother. My husband is 29 and I am 25. We have a very healthy marriage and are very happy. BUT we only have sex once a month. That's right. Once a month - now there are also some other things. We are trying to get pregnant naturally but we are not being obsessive about it. He is always touching me, grabbing my butt/boobs etc. but we just don't hav e sex regularly. What could be up?