My ex, let's call her 'Hoe'. She was gorgeous and had a fat ass (I'm an ass man), but she was incredibly cunning, manipulative and broken in her own way. She gas lit me and abused me (psychological and physical on occasion) for a couple of years, and it's ruined my confidence, how I perceive my self, self-respect and my ability to form new relationships.
She would yell at me, laugh at me, take my phone from me and read through it, tell everyone around me, family and friends, how much of a terrible person I was. She would tell me if I spoke to other girls - some whom I'd known since primary school - she'd break up with me; if I went out with my mates, we'd break up; she'd kill herself if we broke up/I talked to specific people. I had to delete my facebook, I lost so many friends because I lived in fear of losing her, she made me feel like she was the only person who cared and wanted me; other friends gave up on inviting me out, and the majority hated her. I was never able to salvage those relationships.
The kicker was how the constant accusations of cheating. I wasn't, but it turns out she may have been. She'd get really secretive and disappear for a night. I happened to meet with an ex of one of Hoe's guy 'friends' a couple of months after we broke up at a party - She told me that hoe had emailed her abusive messages, claiming that this girl had stolen her man and that they had been together while until she came along. If that last sentence was confusing, basically the hoe was banging another guy while with me. I never hit the hoe up, I thought it wasn't even worth delving back into that black hole, so I'll never know what truly happened
I'm rambling on a bit, but it's nearly 3 years since that relationship. I met a girl last year and she has redefined what 'normal' is to me; We don't fight, we enjoy each other's company, she doesn't belittle me, hit me etc. It took a long time, but I'm on the mend.
I finally saw someone about some childhood trauma I 'experienced', and they showed this wheel with a number of abusive relationship symptoms on it, hoe fit every. Single. One. Hindsight is 20/20. If any of this resonates with you, seek help. Otherwise it'll slowly chip away at you until you're a miserable husk of a person.
This has been surprisingly cathartic, thank you OP