You love your ex, and he loves himself. He loves that you love him. He does not love you.

There is the obvious: your choice to continue letting him come back whenever he's bored or looking for an ego boost is not respecting and valuing yourself. And the not so obvious: never drawing the line for his bad behavior is not a loving thing to do. When you love someone, you have to expect them to treat others well and be decent. You have to expect them to grow and work towards being better. And you have to have a final straw because you cannot effectively love someone else if you don't even know how to love yourself enough demand others treat you well. Sometimes loving someone is letting them face the consequences of their actions, and then loving yourself enough to know you deserve better. He needs you to let him learn from his mistakes so that he doesn't treat others badly, and you need to break away from this pattern because he's got you stagnated in this cruel place of home and sorrow.

I promise you that even if he were to change tomorrow and you were to take him back, there is too much damage there to move forward. You may have a nice period where you relive the past, but you won't have a future.

As for school, since you've deferred that's okay. But use this moment in time to learn something else. I don't mean take classes, I mean like get a job or internship or volunteer position in something you think is interesting. Like dogs? Volunteer at the local shelter. Enjoy architecture? See if a local architect will give you an internship. Think screen printing is nifty? Get a job doing hats and t shirts.

Don't think about what's sensible or useful or whatever... get a dinky hold you over job while you look for something that speaks to you and go after that. There aren't a lot of times in life where you can do something like that, so grab on to this one. Even if it seems weird or dumb.

And then save and plan for college. If you get bored do some local community college classes to get gen eds out of the way (more space for electives later this way!), or if your university is nearby see if you can audit a few classes in different departments so you have a head start on what major you want.

And pick something at school that you really want to do. I suggest a study abroad. I regret not doing one - I was too practical and thought it too much money and time. But I was wrong. You don't even have to do one with your school. Research options for places you super want to go, and then start saving or studying towards that. It will be worth it.

Honestly it sounds like you're a bit afraid. Totally normal, btw. But you learn to channel fear I to anticipation, and that's where you find success and vibrancy.