Sex problems with partner

Katie
We have always had great sex and experimented but around 6 months ago things changed. He could no longer make me orgasm.. I found sex very boring with him. There is no excitement there anymore.. I want sex but when we come close to it o back off and pretend to fall asleep because I can't be bothered... I just think it's always been me that has done everything and Iv got to the stage where it's just more of a hassle. Last night I got horny and asked for sex then as soon as he touched me I backed off and blamed it on being pregnant :/ what do I do? It's not like I don't have a high sex drive because I do and he now that.