This isn't just about intimate relationships, this is about relationships in general.
There's only so much someone can take until they start losing love they have for someone.
They can apologize for their mistakes. You can forgive them for their mistakes. But when they continue to repeat the same mistakes they say they are sorry for, it's time to let them go. They aren't sorry. It becomes a habit they just say, to just say. If they really were apologizing, they would put in the effort to change.
Don't allow someone to mistreat you or use you when it's convenient for them. That's not respect. That's not having love for someone. That's out of their own greed and wanting power over you.
I've allowed people like this in my life for too long. Time to let that sh*t go. I know my worth. I know my value. You should too. No one is better than another. It's just about having respect for another like you would want in return.