low sex drive?

I'm not quite sure what's going on with my hubby. But he's been home from a deployment around 2 months now. Anyways he seems to have a REALLY low sex drive lately (since being home). I know that he isn't cheating because unless he's at work he's home or I'm with him. And throughout the day he will come home on breaks. He spends very little time on his phone. Like 10-15 minutes every week. I have access to his phone at all times and I'm usually the one to carry it. (I don't snoop, no reason to.) he doesn't really answer anyone, even his dad and siblings go to me to get ahold of him. I just dont understand the low sex drive since he's been home.