TLDR: -How do I enjoy my life when my reasons for living feel pointless?

-Had unicorn at 14ish-16 but I got depressed during because my dad had a gruesome death and I started fucking party girls and partying way too hard. Biggest regret of my life

-Family life was fucked. Lived in a trailer with no heat and lost electricity often, wasn't given food or water. Family did meth. Was kicked out at 18 because they didnt get a child support check anymore while still depressed and 6'1 120lbs, no degree, no license or car, no skills.

-Spent a year living with relatives far away and used the thought of my first girl to self improve. I joined the Marines in the infantry, did 2 combat deployments and reinvented myself.

-I got out and now im finishing a degree in engineering (senior). i own my home and own my truck. Im in intensive therapy for my previous life and combat deployments. I was married for a bit but got out of it when i realized AWALT and she started showing signs I didnt like so im free.

-My problem is now that my ex is married (literally with the guy for 15 years from the moment we broke up) I find myself finding no reason to live and I was using her as motivation to keep grinding. Now the grind seems pointless. I enjoyed combat sports but i had a bad back injury and don't want to risk it so now i just gym / cardio.