Anxiety

So I am 22 and have been with my boyfriend for about 7 months now. In his past relationship, his gf and him had sex all the time but that was the only thing keeping them together. We have only had sex a few times and every time after we have sex I think the worst and think I might get pregnant. I’m on birth control and we always use a condom and he pulls out. I know that my chance of pregnancy is very low but I still can’t help but think negatively. He doesn’t pressure me to have sex but I know that it bothers him that we don’t do it more. We have had multiple conversations about my fears and that I shouldn’t worry as much. But i still can’t get it through my head that I will be fine.

He promises that he is okay with waiting until I’m really ready to have sex but I can see that it bothers him that I’m not willing to do it more often. I’m pretty strong willed so I’m not going to just give and cause myself all kinds of anxiety but I really don’t know how to get over my fear.