I know what you feel. Although once you get to a stage where you feel like your guts are being ripped out every time you see them, you are probably past the stage of "what have you got to lose?"
So, take my advice, dont let it get to that stage (unless you love the thrill of the chase, which i do).
If nothing happens from it, sure it will hurt. But fuck, regret is something that is much worse. And it stays with you for a long time. For me, its been over a year now and hes somewhere overseas.
So just do it. Our choices are half chance, and so are everybody else's.