getting hard

My boyfriend and I have been dating for 4 months and we have a lot of fun and we make each other feel great emotionally and physically. But we havent been able to have sex because he has a hard time staying up. He treats me very well and makes me feel so good in bed orally. I cant help but feel like its my fault even though he swears its not...Does anyone else have this issue and how did you deal with it? I love him a lot and this isnt something that would make us break up but i want to please him as he does to me but i cant because he cant keep it up