Cumming

No matter what i do with my boyfriend he won’t cum. I’m not the best at blow jobs but he says that’s ok & he’s helping me get better by practicing. One night we had sex & he was really into it, he still didn’t cum. The other night I tried again with the blow job & he didn’t cum. He says it’s because he’s been watching porn since he was like 12....but I’m still scared that I’m not good enough for him. PLEASE HELP ME!