Have you ever been in a situation where you know the outcome was horrible, terrible, embarrassing, and utterly humiliating and then some kind of realization makes it feel even worse?

Last night, I realized that I was probably in the way (fatalistically speaking) of my ex getting together with my former best friend. Like, if I hadn't existed they likely would've ended up together anyway. At least before I felt like I somehow brought them together by introducing them. Why am I always the one that is impermanent and the one that doesn't matter in these situations? I just wanted to matter in the situation, even a little bit. Even worse, why do I still have realizations like this 4 years later?

I just want to stop thinking about it but every time I have a new realization I hate myself again, a little more.