First time sex problems

Patient: Me and my boyfriend have been together for a few months now and want to take the relationship further by having sex. we’ve talked about it together and think we are ready, we’ve both been naked together several times so know each others bodies ect. we tried having sex one month into the relationship and he couldn’t get an erection (we blamed this on it being far too soon and we just weren’t ready), we tried 3 months after that and he still couldn’t. he gets erections when we kiss and are naked together with skin-to-skin contact but as soon as a condom is put on and we want to get intimate he doesn’t get one. he’s worried something is wrong with his body and i’m just curious as to why this is happening to him? we thought it was because we knew when we were having sex and said what day, even talked about what we were going to do to each other but i’m not sure it is that. What’s happening? his esteem is going rather low because of it. he thinks this could be a case of nerves and has suggested taking like a viagra pill so he has more of a boost, also we’ve suggested i go on the pill incase hisbody has a problem with condoms. what do you think?