can't keep it up

So I've been dating this guy for a while now, and yesterday I stayed over at his house. Things were getting intense, and we decided to have sex. And he was pretty hard, and I was pretty wet, but when I put the condom on, he lost his erection and couldn't get it back up. He was embarrassed and felt bad about the whole thing. I really like him, and I want to give him pleasure. Plus I really do want to have sex with him. But I don't know how that can happen if he goes soft when a condom is put on. Idk what to do. Any suggestions?