No sex in a month!

Ohhhhhh myyyy godddddd. Ok so me and my boyfriend have been together for almost 3 years. We have twin girls together and I'm 4 months pregnant with our son. Like any relationship we've been thru the mud and my boyfriend has a history of cheating and/or communicating with other females. It was hard to deal with but that was literally the only bad thing about him. Literally. So I forgave him and we moved on and haven't had any issues lately. Except one.... we haven't had sex is over a month! The vibe in the house is fun and vibrant and we really enjoy each other's company. I don't suspect that his cheating again because he has become a complete home body and never leaves. Maybe it's the parenthood kicking in. Our twins are 1 and a half and crazy as can be lol making it hard for us to find alone time. Or maybe it's that our relationship has become about more than just sex and that "sex every day/night" is a myth in real relationships. Help please because it's driving me crazy thinking that he's nothing attracted anymore.