Why am I obsessive over this?

[Grilleall]

I appreciate good answers & no judgment against my question. Thanks in advance. I started dating my bf a year ago & we had facebook etc, a certain girl would try to be all buddy buddy with my bf & it infuriated me. She would even be snarky & that's when me and my bf decided to delete facebook. She would hang around some of his friends (of course he was always with me & never hung out with those friends) and we never hung around them and drama happened now I still obsess over what she's possibly doing. I put it in my brain that my bf likes her and she's way better than me. It's taking a toll on me. My bf and I had serious issues because of me and this problem. I feel like she's prettier, cooler or whatever even though my bf says she's gross and not someone he wants to be around at all & even her personality is depressing. I have been told plenty of times how much my bf loves me or even likes me in comparison to her. and yet I find myself looking up her social media.... Why am I doing this

[Jennifer Connelly]

Because all girls get like this at one point or another, just try to relax, stop looking at her or anything about her act like she's a nobody. If your bf and others tell you he likes ER loves you just accept it. I hate admitting it but whenever I got like that it was called insecurity and jealousy. You're better than her so just be positive and be with your bf!

[Brooke]

All girls do that. You have to think of it this way. If he loves you, he won't do anything with her. You have to have trust in him to make the right decision.