I am in my 1st and hopefully only sexual relationship, The reason why I say hopefully only relationship is because I love my partner so much!
I have a problem that is really upsetting me and my partner is getting upset also because I am getting upset about my problem.

My problem is that when it comes to sex, I fail!, But you see everything else is grand, Like when it comes to Oral sex or anything else my penis works properly, but when it comes to sex it doesn't always work.

I am not a virgin but I have not had sex to the full extend, as in I have not had an orgasm during sex, When it comes to sex me and my partner takes things slowly, like slowly taking off our clothes and stuff it takes about 15/20 minutes to get down to action, when me and my partner are in the room at the beginning of sex I am very erect, like when we are taking off our clothes and taking things slowly, but after, when our clothes are off, sometimes I don't feel sexually excited anymore, and when I do feel sexually excited and when I begin to have sex it feels good yes, but after a while my penis looses its erection and goes soft.

I use durex condoms and they don't seem to help, because when I am having oral sex without a condom everything is fine, You see during sex I don't feel entirely comfortable showing off my penis or body, but I will have to deal with that I know, I am also nervous before sex because I am utterly afraid that my penis will not work and it will upset me yet again, The 1st time me and my partner were about to have sex I was not expecting it at all, and I got freaked out and could not get it erect, It was like my penis was afraid! I got upset and have thought about that happening every time we go to have sex, My partner also offered to leave out sex because it is upsetting both of us, I wasn't entirely happy about it, but after a while we decided to NOT leave out sex.

My partner is very supportive of me, because everytime I fail in sex she says "don't worry about it" and stuff like that, I am happy for that, but I feel like I am letting her down a lot because I can't have sex and it hurts deep inside!

I just want to know if there is anything wrong with me, because if this keeps happening I am going to get more and more upset, could it be the condoms? or could it be the whole nervous/afraid thing before sex that I am thinking about my penis going soft and not being able to have sex? Could this be all in my head? Or is there something wrong with my penis? Please help me as soon as possible, Thank you very much