boyfriend doesn't want to have sex

So I got pregnant but had a miscarriage in November. My so and I broke up before I told him so right before we got back together I found out he slept with someone else, so I told him I wanted him to sign his rights away. Whatever, anyways I had a miscarriage like a week later. We had sex in the beginning of our realitionship like multiple times a day, it was amazing! Then later on we started only have sex a couple of times a week. Then after my mc once a week. Now I haven't had sex since march 27. And when we do have sex he don't last long. What do I do? I've asked him multiple times why we don't have sex but he says he doesn't know and to stop asking. We live together and have been together since I was 17. Out 2 year is coming up in may and I'm just concerned he doesn't want me anymore. 
Side note: he didn't want the child