Not at all to sound cliche buddy, however, your happiness isn't really an externally controllable thing. As far as your ex, you're young enough (my daughter is in college) to have more great experiences & relationships ahead of you than in your past, on top of the fact...you seem to be mature enough to ask yourself hard questions that actually lead to better answers. Keep your head up buddy. Not out of some sort of positive mental attitude technique but because, that's the only way your eyes will be open to new opportunities & see forward 🤔😉💯