My parents split two years ago on the day before christmas eve, around 3 AM. It wasn't pretty, but I'll give you the tl;dr: Mother cheated on father, caught in the act, this had been going on for weeks. Only discovered it two days before Christmas. Gave her a chance on 23/12 it all went to hell again. So at 3 am, after shit hit the fan again, we (as a family) decided to lock the door with a special lock, so she couldn't enter.
This, however, is not the reason why I broke contact with my mother. Let's see, my mother has always been a manipulative person. She's a control freak and extremely jealous. I wasn't allowed to live my life the way I wanted to because she never got to. She always told me I mirrored her life; I was a copy and would have the same issues, so she made me see multiple therapists (some of them agreed my mother was the whole problem). She controlled my father, and he couldn't have friends without her getting jealous, he couldn't even text people without being accused of cheating.
In the weeks leading up to her leaving, she always told me she didn't want me. I would have to stay with my dad, this hurt. So much. So, once she left my family broke down. She did not even talk to us for the first months, let my siblings be. One is only 10, and she broke him. She left us with so many debts, because she failed to fill out paperwork and also stole from my father's company and our insurances. She ran off, left us to fend for ourself and then suddenly acted like nothing ever happened. I didn't take this too well, and had to break contact to keep sane! I could finally reconnect with my grandparents after she made me break contact with them, she was afraid I'd find out about what she had done to them. She had been stealing from them AND from her charity projects repeatedly AND from the companies she had been working at. Oh! And my savings account my father set up for me is empty! So, now I'm struggling to pay for uni! Hooray!
So yeah, broke with her to get my freedom and ability to live my life how I want it to, instead of the live she wanted me to live.