Tell her that you are into threesomes and if she doesn't do it you are going to kill yourself. Then just stare at her.

Obviously, she doesn't care about you as much as you do her if she would place such a burden upon you. You could take her aside and have a serious discussion, such as, "If you really cared about me, why would you put that kind of burden on me? It really worries me." Or, as everyone else states, tell her parents. Or, if you're really worried, call the cops. They can place her in a hospital for a few days and watch her, if they feel necessary. And honestly, she probably won't do it--most people who say that are just looking for some sort of power over you, or insurance that you won't leave... You don't deserve to be treated like this. Do what you feel is right for this situation.

Eff that man.... Don't let her pull that on you. Talk to her family, let them know she needs help if she seriously does that. A lot of times it's a cry for attention and needs to be addressed professionally. Either way you are responsible for no one but yourself.

wow :) she seems like a totally cool person to hang out with

Hey, it's not your fault she has supposed "emotional instability." Let her suffer — it'll build her character.

FYL! hahaha

tell her you'll kill yourself if she as much as LOOKS at another guy. problem solved. and can someone please tell me the full form of 'OP'? thankyouverymuch.

Somebody's obviously been reading Twilight. Dump her ass like a hot potato.

Just do this, cut her arm and say we're done. You already cut it.

Anybody who cuts themselves and claims they're gonna kill themselves over the slightest bit of an emotional letdown is just craving attention. If she was that emotionally/mentally unstable, she would have offed herself a while ago and done the whole world a huge favor. Break up with the crazy ****. Stupid bitch; I hate it when people do shit like that. "Waaahhh, I cut myself so I know I can still feel!" Ugh.