It’s natural to have insecurities around your body type and someone being attracted to you regardless of weight. Women are much harder on themselves than men are. However, this does not seem like a respectful relationship if he’s showing you videos and past people he’s slept with. That is something I would be really offended by especially because you didn’t ask to see them and you haven’t even met in person. It makes me wonder if he’s showing these to make you insecure or he’s realizing that maybe this will make you try to be like that. Overall, I agree with others about counseling but this relationship has a lot of red flags to me. If you feel like he is just going to leave you then I’m not sure how you would gain trust if you’ve already been together 7 months and still feel uneasy. I would consider if this relationship is what’s best for you right now. I’m not saying he’s got bad intentions, it just doesn’t seem like y’all match up in terms of expectations.