My girlfriend told me she would kill herself if we broke up. What should I do?

Okay here's what happened: Took place at a park at night by the way...

me: I think we should break up. it's not working out anymore. And I honestly haven't been able to see you the same way after cheating on me.

her: oh no. I say when it's over not you. *she smiles creepy as she says it and I made myself laugh because I thought she was joking.

me: no but I'm serious. I think it's time for us to part ways. we've been going out for a few years already and I've already thought about it and I don't want to be together anymore.
*she starts crying and I get embarrassed because there's all these people walking with us. IT'S A PARK AFTER ALL. Maybe not the best place but that's irrelevant.

her: If you break up with me, I won't see any point in living anymore. I'll kill myself. please don't leave me.
*There's these girls that look at me and her as they are walking by and I just felt so guilty and like a as***e so I gave in to make her stop crying

me: okay nevermind.

her: you promise you'll never break up with me?

I tried staying quiet but she asked again and started being even louder. I was so annoyed so I gave in again. and she even made me say it.

Anyways, I tried it in a private matter and that was a whole lot worse. she started yelling at me and my little sister was in the house and I told her to keep it down because my little sister could hear and she said she didn't care. she left my house and came back and I couldn't just kick her out. so I let her stay and I've been trying the same method 4 times already and I don't want her to hurt herself or be all emotional during a college semester. She basically says she'll hurt herself if I break up with her and I'm a really nice person so I just stay with her because it makes her happy and I feel bad.

My girlfriend told me she would kill herself if we broke up. What should I do?
Add Opinion