This pattern of toxic relationship behavior isn’t healthy for either of you. I’m concerned that it’s been going on for two years, has increased in severity, it’s consistently your role to apologize, and she’s not getting what she has repeatedly said she wants (a break-up). Rather than waiting until conflict occurs to discuss the health of your relationship, discuss this problematic cycle of behavior during a moment when the two of you are getting along well. Be open and honest and LISTEN to what she wants instead of making assumptions. Ask what she wants out of the relationship, whether she wants to break up, and if not, why she claims she does? I suspect there may be some mental health issues involved, but that still doesn’t mean you two belong together. If you truly care about her, you’ll honor her wishes.