I care that my best friend had sex with my ex after a breakup with me and left me suicidial
Do you think that this had a bad effect on you?
I hate her for it. I thought she could be a better friend to me and I feel hurt because I really thought she would treat me better.
It wasn't okay that your friend and ex hooked up, but for you to hate your friend is not right. People make mistakes and you must be the bigger person and forgive her.
I can never forgive her for betraying the trust we had for each other.
At least it happened after you broke up, but if you can't forgive her, it might be best to just move on.