I need advice pls

My boyfriend and I been together for 2 years and always had great sex and we live together. Well we had sex today starting this morning and some reason he couldn’t cum he didn’t know why and he swore it wasn’t because of me, and now about 30 min ago we had sex again and some reason he couldn’t come and I’m trying not to think so negative about it thinking it’s me or he cheated but this has never ever happen before! Of course I was little upset and he blew up on me saying he doesn’t know what’s going on and why he can’t and he doesn’t like this shit and assuming I’m saying it’s his fault. Idk why this is happening 😭