Feeling Insecure in My Relationship

I NEED FEEDBACK I'm so sick of feeling insecure. I don't know how to stop. When I talk to people they say it's my partner's fault, and to an extent it is, but I don't want to be stuck choosing between being with them and feeling like shit and not being with them. I've tried and tried to not be jealous and let it consume my thoughts, but there honestly isn't a day where I don't think about them looking at other women. They follow hundreds of Instagram thots (not that there's anything wrong with insta thots- get that bread lol), and it just hurts. these are girls 10 sizes smaller than me with perfect bodies/fake bodies. When they're "doing their thing" to that it makes me feel like shit. These girls don't resemble me at all. They've admitted that my "pictures get old to them after a while". It hurts. It hurts so fucking bad, but I have no one to talk to about it. I just want them to want me and only me. I don't really mind them watching porn, but when they're retweeting, liking, etc. these women's posts it hurts. I don't know what to do. I've brought up ~5 times how it bothers me and makes me feel like shit, but they don't do anything. They barely respond. I can't a way to communicate to them without feeling like a whiny bitch, so instead I've distanced myself emotionally from them. I feel like I can't trust them with my emotions, especially after I said they've been acting weird and they called me annoying afterwards. Anytime I try to communicate, it feels like it blows back up in my face. I'm so lost.. please give advice.. It just hurts and I'm afraid I'm going to relapse..