Help, He Kept Going Soft & I Don't Know If It Was Me

I recently tried to have sex with this guy that I met online. We've talked for the past year but just met a few days ago. All started off well, and he seemed very hard and put a condom on and began penetrating but then he stopped, he said I hate these things, took the condom off and we did some oral. He got hard again and put a new condom on and the same thing happen, this time he said I was too wet. So we tried the oral again and he got very hard again, it was great, so we tried a third and last condom we had and I tried getting on top, but this time he said that I kept pushing him out, lol, this is probably true because I've only had sex a few times and I am very inexperienced and also still tight and scared too of it hurting. I told him at the beginning that I didn't want it to hurt and he said he would go slow. Sooooo, we tried and it was good for a few seconds but again, he went soft and took the last condom off and we did oral agian. Now, it only took a few seconds for me to get him hard again and a few minutes tilll he came. So, why couldn't we have sex? I really wanted to and I went to the doctor the next day because I thought it was me and the doctor said that all was normal with me but I needed to try and relax and not get scared of the pain, because that would make it hurt more, when it shouldn't. I thought maybe it was my body, I'm a little curvy but he said he likes my body and when I tried to keep covered, lol, he didn't want me to. Any reasons why he kept getting soft? Also, if he kept getting soft and needing to change the condom, does that mean it slipped off and could there be a possibility that some pre-cum got inside of me that could lead to a pregnancy?