Sex life is non extistent

Hey girls, so my boyfriend and I have been together for 2.5 years and have an 18 month old. We always hooked up before the baby and it was great. Since the baby its declined a lot especially since we were co sleeping with the baby until recently but now that we're finally not and my boyfriend and I can sleep baby free in the bed again he never hooks up with me anymore. I initiated it once about a month ago and he hasn't still tried anything. I don't understand why and I've straight up asked him and got upset about it to him few times recently and the excuses I've heard so far just don't make sense. He says he hasn't shaved down there in a while (ok?) And that were in someone else's house so that's another reason why(noise). Were renovating our house right now so are in my friends parent's basement. But that's never stopped him before from hooking up with me if other people were in the house. And last month we were on our own and he never tried. Idk if I'm not pretty enough lately or what? I'm always taking care of our baby so I'm exhausted and don't look as done up could that be it? How do I figure out the real reason or try to fix this cuz its making me really depressed and I feel undesirable lately. I haven't gained any weight or anything and I know hes not cheating but yet he always talks about marriage. Why do u wanna marry me if u don't even wanna sleep with me anymore? Help