His life didn't get better because you aren't in it... he is using his time to focus on himself and it is working...that's really all.
I'm sorry you are having a hard time, but I like that you want to study again. That is a positive thing.
You work at a bar but have other skills, things you can do. Perhaps if you like the idea of working in a small business, you could work towards being the manager, book keeper or something that will use your brain in a different way.
Perhaps it is time to consider moving yourself...maybe to another country...

If you want to brain storm, I can help you with that.

Also, as an aside, have you ever done any sort of skills assessment, personality test type stuff? Sometime they can be very informative in steering you toward something that would make you feel the most satisfied. Look up Meyers-Briggs to start, see what you think...
Best of luck to you