Mental health? wazzat?
Seriously though, it's obvious no one here is a medical professional, but I honestly feel this is a safe space where people can, in fact open up. On my part, I'm a pretty good listener, so while I can't do much for anyone in practice, I can at least do that.
Who needs a medical license when you've got style? Oddly enough my degree required me to study psychology for 2 years. I am far from what I would consider a medical professional but my armchair is extra comfy. Also, I'm rubbish at this sort of thing but if my assorted and slightly drunken ramblings help anyone in any capacity I'll consider that my good deed for the day. After all, it's the thought that counts, no?
Now that the preamble is done here's how I see things. What a lot of you need is closure that will allow you to move on. One thing you need to understand is that you're not the only party that took part in the ensuing altercations and conflicts in your life. Other people were there too and they too had their failings. There is no such thing as a prolonged relationship between people in which one side was squeaky clean the entire time while the other was to blame for everything. It just doesn't work like that. What can we deduce from this? The easiest method to move on would be to sit down together, have a heart to heart and part ways. Unfortunately it doesn't look like that's an option. I have no way of gauging how truthful any of you are in your confessions (and trust me, I've seen people lie about much worse things) so I will take your word for your circumstances. It's fine to ruminate on and analyze everything that's happened but you can't dwell on things forever. It's good to learn from your mistakes but please recognize that the other person also contributed to the mess. They may try and lead you to believe that you're the only one responsible but that's just their coping mechanism. Could be that they're dealing with issues too, sure, but it's like getting bullied. Do you deserve to get bullied because your bully is dealing with a tough home situation? NO. You can feel sympathy for them but never justify what they put you through. Letting them make you think it was all your fault will only make you spiral into a very dark place you don't deserve to be in.
So, what *do* you do? In all honesty, I don't know. Yeah, it sounds like a cop out but the reality of things is that I simply don't know you well enough to be able to nudge you in the right direction. What I can tell you is that you need a goal, something that you can and will put an effort towards, something that will distract you at first but will fulfill you and become your aim later on. Someone mentioned reading Seneca and getting fit and they had a point. If you're having a hard time putting together a framework through which you want to see the world relying on the greats who've come before you is not a bad idea. All I'll say here is that I'd recommend ancient philosophers for your reading. Those who came later tend to have their works coloured by their contemporary attitudes towards politics or religion. Sure, you could say the same about Plato or Aristotle but their works tend to be universal enough (or too far removed from our time if you want to be cynical) for them to still be applicable while the likes of Spinoza, Kierkegaard and especially 19th century German philosophers might help you understand the world at large better but they're not going to do your mental state any good as they can be very depressive at times. Minor honourable mention goes out to Max Stirner and his 'I am only my own when I am a master of myself and not governed by other things'. Being at peace with yourself will do you good. As to what that goal is, it's up to you. Maybe it's taking up drawing, maybe it's the gym, maybe it's vengeance (I know a girl who pissed all over her abusive ex's grave and according to her she had never felt more liberated). Just make sure you stay on the side of the law if you ever pick the latter, OK? You don't want to ruin your life over getting back at people who most likely don't care anyway and have that hanging over your head now do you? Either way, just try to nurture yourself and you'll seize the world I'm telling ya.
TL;DR - there is a time for self-flagellation and there is a time for understanding you can and should move on.
And there we have it folks, possibly the worst post I'll ever commit to this forum. I've tried proofreading it twice but my beer goggles are preventing me from seeing straight so if anything's wacky, blame drunk Clippy. Either way, lots of love and I hope you can dig yourselves out of the holes you're in. And if I helped you in any capacity I'll wear it like the badge of honor that it is.