Most Helpful Guy
Wow! This mystery girlfriend sounds really mature and together. She couldn't simply ask if you knew he had a girlfriend and instead had to assume you were just all about seducing her man. Based on what you explained she said to you, I can kind of see why her boyfriend went looking for something better. The only problem is he forgot to pull the plug on the idiot.
The suicidal ploy is bullshit and is his attempt to control and manipulate you. I'm not sure why he'd even say that since you probably want to strangle him anyway for being such a lying douche.
Please just walk away. I'm really sorry for you and I know it hurts, but get rid of this cancer before it spreads and the crazy girl is at your place trying to break your door down.
Run, don't walk. Just take the high road and say nothing. There's nothing for you to say as everything is now out in the open. He lied and cheated and you can't trust him. End of story.
Most Helpful Girl
... I'm in shock...
I am quite sure as the sun rises and sets in the sky, Blondegreeneyes, that You are Not the Only one who Is-----In shock.
Like yourself, she is devastated, angry and ready to kill someone, and with calling you these wretched names and lashing out at you, I am also quite sure she didn't mean what she says, but like the green eyed monster, she is jealous as sin and everything else... within, much like you here, dear.
Drop him like a hot potato now. Move on. You know his story, he is not going to leave her or the baggage he has with her, nor the history, and even if he would pick you tomorrow, leaving her behind, you could never trust him.
Don't become what I call in a "Triangle Threesome," where you are way at the top, looking down, from side to side, at the both of them.
He is a loser to boot, boot him out of your life and don't look back. He will never change and once you dump his sorry butt, he will be looking and lurking for another to keep secret... maybe even longer this time.
Good luck. xx