<human>: Like the title says, I can't get rid of the pang of anxiety I get when I see my ex unexpectedly. She cheated, and we broke up. And beyond that, our personalities were complementary, but there were some fundamental differences between us that would never allow us to get married. It truly is for the best that we aren't together anymore.

I'm engaged to someone who is in every way better for me. Same sense of humor, similar taste in movies and TV, big concert-goer, same religion, etc. I couldn't have imagined a better person for me.

The problem is, even though it's been years, I can't help but get those same nostalgic feelings when I see my ex's name pop up in mutual friends' FB posts or find a gift she gave me years ago. I know that logically, I have no reason to have any feeling at all about her, since we were incompatible and I'm much happier with someone else, but my emotions just aren't keeping up. How do I stop these feelings from occurring? I don't want them to interfere with my current relationship.

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: Engaged dude still hung up on an old gf, even though I know I don't want to be with her. How do I shake these feelings?