Feel ya. My ex of two years cheated on me. She wanted to apologize and try to be friends again and start talking. Recently when we we're out to coffee she said the guy she cheated on me with and her weren't talking anymore and she lost the love of her life. Fuck me.
Only reason I'm alive is spite. To prove I'm better.
Truthfully from a neurological perspective you need to release one of the following: endorphins, testosterone, dopamine, or serotonin. Most of them release together in some way, shape or form.
Sounds like you need a hobby bro. Go to the gym I'd say is the best. You feel better about yourself while releasing those hormones. Go fuck something (consentually), make some art, find a hobby. Be okay with who you are. Never give up, if you have nothing to live for you have nothing to die for.
Time to be the greatness you were meant to be.