My boyfriend 'had sex' with his cousin at a young age
My boyfriend and I have been together for a year. For what ever reasons, I can't find it in me to fully trust him, because of this we have quite a few arguments and fights. One night (recently) he left my house after a big fight but when he got home he called me and apologized. We spoke on the phone for hours as I told him I want no secrets between us and that he can and should tell me everything. So he decided to tell me about an experience from his past. He said, and I quote, "When I was young, around seven or so, I had sex with my cousin."
He said they were 'playing doctor' and one thing led to the next. He said they had no idea what they were doing but it happened. He apparently never told a soul about it until he told me and he hardly speaks to his cousin, she lives in another state.
First, I wasn't sure if I should believe him, then I felt sorry for him and asked him to talk to a specialist about it and lastly I told him we don't ever have to talk about this again.
It weighs on my mind though. I don't know if it bothers me more that it happened or that I'm not too concerned about it.
I am concerned though, I'm a little scared and worried. I just don't know what to think of this.
I know this isn't 'Normal' but what is it and what should I do?