So me and my boyfriend have known each other since we were children and we did not start dating until I was a sophomore in college and he was a freshman. However, a year before in October 2019 we began talking. I explicitly asked him if he was seeing anyone or talking to anyone. Then February 2020 comes around he he says that it was hard to talk because I was away at college. I was kinda hurt, but I understood. Then August comes around and he asks me out, I said yes. However, I found out that in December 2019 he had sex with his ex, and in February 2020 he started talking to a girl in his high school. He said that she was not the reason he stopped talking to me, but I always tell him that it's a coincidence that he cut me off and started talking to the girl. And to make it worse I found out that he initiated that relationship and she was the one that ended it. And right when she ended it that's when started talking to me again. He was honest enough to tell me, and he gave me the password to his phone so I know that him and the girl don't talk anymore. But six months into this relationship and I'm still hurt by the situation. Should I leave the relationship or stay?
Only you know the full situation, so it is difficult for an outsider to advise. Young people (particularly guys) take a while to mature, so you will have to decide whether he has grown up sufficiently to have and want a long term relationship.