I would suggest changing the perspective on this one to why do I have a partner that I feel a need to control or why am I tolerating an abusive relationship. It's never about the other person as we don't control other people. That's my main suggestion to this entire question, but I'll break it down a little bit more.

The best way that I've found to handle relationships with others that I find in some way toxic is to clearly define my own boundaries and assertively express them. For example, if someone gets mad and yells at me or throws things, I tell them how that makes me feel and clearly explain that I'm not going to tolerate that behavior as I don't need that kind of stuff in my life. If they cross that boundary then I leave.

Obviously situations and relationships are complicated and we all have to figure out what works best in our own lives. I try to approach things in a way that is as unbiased as possible and always consider that it's not up to me to change anyone else. If someone genuinely makes a mistake, that's easy enough to forgive, but if mistakes keep happening over and over again, then there's likely more going on there.

No one owes me anything and I owe no one else anything. I am responsible for my own boundaries and other people are responsible for theirs. Respect other's boundaries as best as I can even when they aren't respecting mine, it's easier to leave a situation than to explain why I did something that I regret later.