Break ups are real shit but I can tell you from experience that there's far worse that can happen. I've broken up with or been told I can't be a partner for 4 years now. Accepted being single but got far bigger problems.
I know it hurts a lot as I've had it happen to me frequently. (Got divorced and had subsequent relationships go sour) - I just became numb to it after a while.
Went through the same thing a couple of months ago, It is my reason to CTB as well, nothing is helping in my situation, I don't know if I ever can overcome the pain as it's different for everybody. I can somewhat deal with the loss itself and accept being single, but to be thrown out like a dog while she's being with someone else, it makes me suffocate, especially since we were each other's first and made promises to do our best to ger married.
I went through so much shit in life, including being molested as a child, and being falsely accused of a crime I didn't commit while having my reputation tarnished because of that...But this is easily the worst one yet, I don't see it as CTB'ing because of the person or their love but rather to end the pain they've caused me.