I'd ignore her for sure. Focus on going no contact and moving on. Tell her if she really wants to be with you, that she can leave him and you'll give the relationship another chance. But that you're not going to sit around indulging some stupid fantasy about how some day you'll have a better future while she's off f*&#ing another man. If you do, then you're just being a doormat.
Try to focus on moving on. Let her see what it's like to lose you by being completely out of her life. If that's not enough to make her want to come back, then you'll know where you stand with her. You deserve better.
Actually, scrap that, I'm not even sure if she'd be worth taking back at this point. She threw you under the bus after a year and a half just for a guy who'd hurt her and cheated on her. I'd give some serious thought as to whether or not it's worth taking her back if she breaks up with him.
Last edited by VerticalMoon; 07-07-13 at 11:43 PM.
“This planet has - or rather had - a problem, which was this: most of the people living on it were unhappy for pretty much of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movement of small green pieces of paper, which was odd because on the whole it wasn't the small green pieces of paper that were unhappy.” ― Douglas Adams, The Hitchhiker's Guide to the Galaxy