There are people who'll try to maintain a relationship at ANY cost to themselves, be it with a parent or sibling, friend or lover. If someone makes it impossible for you to interact with em in a loving and harmonious manner, you should cut that tie and flee.
Here's the deal: You can't MAKE someone love you. You can't make 'em care about you as much as you do them, and you can't have a functional relationship with a dysfunctional person!
It isn't that you're not trying hard enough. It's not that if you just keep at it, you'll finally be victorious. They are SHOWING you exactly what they are capable of~ no more, no less. If you are frowning more than you're smiling around that individual, GET THE FUCK AWAY FROM EM.
Yes, you'll miss the drama at first. Yes, you'll miss the chaos and pain, but your energy and health will soon benefit from being rid of their toxicity, and ya might just find that your attention and focus begin flowing into arenas that are far more productive and rewarding for ya.
Hanging onto a bad relationship is basically like being a hoarder. You don't wanna get rid of shit, because you think you'll need it some day~ but it's really about your unwillingness to free yourself from destructive, energy-jamming clutter.