Going limp....

To make a long story short. I met my boyfriend last year in April. Our relationship went pretty fast, now we are leaving together. When we met I was 10-15 pounds lighter (yes I am trying to lose that weight again, not for him but for myself). Before we used to have sex like rabbits. We haven’t had sex since March. The last time in March he couldn’t stay hard which was odd to me but I just let it slide. So tonight I thought it was a good idea to have sex.... wrong. I got him hard by starting off with some head cool whatever. Soon as we switched to have sex, he just goes limp. This is the second time of it happening so now I’m starting to think it’s me. I am having the worst thoughts like maybe I’m not attractive to him anymore or the weight I gained isn’t what he is used too. Am I tripping or what? Not to compare any guys to him but I’ve never had that happen to me before. Please no rude comments. Any advice how I should go about this? Because this hurt my feelings.