Advice to overcome being territorial

Hi all 👋🏻 , I find myself being very territorial over my bf lately and I don’t know why. He hasn’t done anything to make me feel like he’s cheating or anything like that. But I just find myself getting a little “sour” when I see that he still follows/likes insta posts of almost nude women, or when girls message him, or when he says “that girl (on tv) is my biathlon crush”. I really hate feeling this way because I know that if I actually expressed these feelings to him he would think I’m being controlling which I do not want to be. I am skeptical that part of the reason for me feeling this way is because I’m trying to lose weight/fat and I don’t like what I see in the mirror. I think that if I feel secure with myself then that will reflect in my relationship. I love my bf very much and I really want to go back to the time when I could care less who he talked to or whatever.

Any tips for overcoming feeling/being territorial? I don’t want to be this person but I need help