I feel dumb

Sometimes I feel like idk why my boyfriend is even with me .. It makes me upset at how like everybody was like use to seeing him being with his ex and now he's with me, I feel like people probably talk loads of shit of hoe he can do better, idk plus I feel like his ex looks better than me lol just don't see what's so interesting about me .... I feel like I'm in competition with his past :( plus there's a fucking Instagram with all their pictures on it and shit. He says he doesn't have the password to it & that she does but it just hurts and even though I shouldn't, I still go lurk and look at them. I feel like I can even compete with what they once shared, he even had her name until he got it Covered up. I feel stupid, I truly feel like I shouldn't even be with him and told him to go back to her :'( I know I'm insecure asf