Why can't I orgasm or cum during intercourse?

I recently lost my virginity to my boyfriend, and I love him a lot, but I can't seem to "finish" when we have sex.

We started out just doing oral sex and fingering, he even uses a vibrator sometimes, but even none of that brought me to orgasm. Once we finally decided to have sex, I thought I would finally orgasm, but we have done it probably 10-15 times now, and it still won't happen.

We had some trouble getting started with sex, because I was very tight, and it was honestly very painful for me, and he could not get all of his penis in at first. We are now at the point where I am stretched out enough that it stops hurting and he can insert most all of his penis, however it is still very tight, and although it feels really good at times, I still feel a lot of pressure. Is that normal?

Also, I do enjoy the sex. I get really wet to the point where it is dripping, and I feel intense pressure, and I think I am going to cum or orgasm, but it still won't happen. We have tried different positions, different speeds, and more foreplay, and nothing seems to work. He does have more experience than me, and hes never had this problem before so I think its just me. I dont know if it is in my head, or if Im doing something wrong. I have already looked it up and found it is normal to feel like you have to pee right before you cum, and I have had that feeling before, but I can't seem to push it out or release it. Even though I've gotten to that point, I still havent felt any kind of orgasm, I feel pleasure, but no full body sensation like most people describe.

Is there anything to do to help reach orgasm or to get me to cum? I don't know what else to try and my boyfriend is getting really frustrated because he is starting to feel inadequte that he can't get me off. We are both 20, and although I just lost my virginity, he has experience, Please help.