About 3 weeks ago my girlfriend cheated on me, (with guy M) I forgave her because I've cheated before, and know what it's like to make a mistake. Then, the next week she's at a party and meets a guy (guy D) and he asked her out. She actually said yes... Then the next weekend she cheated again (guy M) She's said she's sorry and doesn't want to lose me, she wants things back to normal.

Well, it turns out that 2 weeks from now guy D is having a concert and she's going to see it. So I pretty much know she's still seeing him, especially since she let it slip that guy M and guy D are the same person.

I am absolutely crushed. My physical health has suffered, I've lost weight/sleep etc...
I can't do this anymore, I'm willing to give her a last chance but I'm absolutely sure she'll do this to me again.

Here's my plan; I'm going to call her tonight and ask her to choose because I'm not going to be in the middle anymore. She still loves me and wants to be with me but I'm going to tell her it's either me or him and if it's him I'm gone. I'm not going to talk to her or anything no matter how hard it is. This is probably going to be the hardest thing I've ever had to do, I just want some input...

Is it the right thing to do? It seems like the situation is too fragile for something like this, but I am no longer going to suffer. Help plz

Also: the 3rd time she cheated, I flat out told her I didn't want to be with her anymore if she was going to do this. She went crazy and wouldn't let me go. I'm so confused, and I have no idea what to do/expect

Would you rather keep her or your dignity?

If you choose the former, you lose both.

So use your balls, dump that bitch for treating you like shit, and next time have some respect for yourself. Then, maybe, your girls will have some for you as well.

Come on dude, you knew what you had to do at strike one. Unless she keeps tripping over stuff and falling on his dick by accident you need to break it off (and by it I mean his dick).

What if she really is sorry and all? Should I stick with giving her one last chance?

If I do just dump her ass like I should, what do I do if she comes crawling back?

Dump her, expect a period of lameness before eventually realizing there's other less headtrippy chicks in the world.
It sounds like she's too far gone to come back faithful.

If she comes crawling back, get some dome and leave it at that.

Wake up man. She not only cheated on you once, and not even twice, but THREE times.

If she comes crawling back, you laugh in the bitch's face and shut the door right in front of her.

You can't let people treat you like that.

This is the only thing you need to read in this thread.

As much as it hurts to hear this: SHE DOESN'T LOVE YOU.

One time, a mistake, might be forgivable. But she's fucking other people behind your back, lying about it, and she's STILL FUCKING HANGING OUT WITH THE GUY SHE'S BANGING BEHIND YOUR BACK. If she loved you, she wouldn't act this way. She's got your balls in a mason jar under the sink, and you can either sit around and be miserable, or do something about it, because it's not going to change anytime soon; you've shown her that she can do whatever she wants and you're going to do fuckall about it.

Break up with that cheating whore; you're holding onto a perception of her that is false. You want to believe that she's the girl you fell in love with, but she's not. Cut it loose.

Dude, she really isn't sorry. She might pretend she's sorry but despite what you may think, people do have control of their actions, and she chose to cheat on you 3 times.

Once should've been enough. Grow a dick.