I need someone to help me stop obsessing over my hubby's ex.?

How can I stop. I know I need to. It's just easier said than done. We have been married a while and I used to think nothing of it but over the years I find myself looking at her facebook page, wondering if she looks better than me, I know it doesn't matter, I just can't stop doing it. I think I'm going crazy. She just got some plastic surgery done and now she looks even better so it is even worse now. Everyone tells me I look a lot better than her but I know they are just saying it to make me feel better. She is maybe 15 pounds smaller than me and she didn't have a pretty face, but she does now that she had that stuff done. Tell me how I can stop being this way. I wanna stop but please don't say just stop. I can't. I know what I'm doing so please don't say, your obsessing or your whatever, I just need some good advise, I feel ugly all the time. Like I can never be decent looking,. I don't know what to do to sop feeling like she is better than me.