Worst breakup you've had / heard about?

In all honesty, it was my personal worst break up, but my partner at the time ended up going back to an old ex, even though both them and I knew, and talked about, that I treated them better, was a better fit personality wise, and wasn't a sociopath like the ex was. They still did it anyways, I felt like crap and broken-hearted for a year and 3 months before I finally started to let things go.

 Then they messaged me again, saying that they needed me, and that just got over a miscarriage and was dumped by their old ex. 

I... probably for my own sake should've just ignored them but I chose to help them and comfort them. And after they got over it for like 3 weeks they decided to go flirt and date with other people, and at that point I just said no. Goodbye, I don't want to be this with you anymore. It was hard. This whole thing was a big mess, but I'm glad it's all in the past now, and I'm healed from it

We broke up she threatened me I blew it off I shouldn't have and now I live with the scars