Rob, it sucks. but the advice you are getting now seems about right.
And please try to avoid behaving badly, picking a fight, sulking, jumping at excuses to open hostilities. Try not to show you are hurting. If what you suspect is true, she is on a high right now. Don't let her compare that to a whiny, clingy, weak man.
Don't even think about the next step yet until the sickly feeling passes somewhat and you are more logical. Take a pill and sleep if you need to.
Me 42 W 39 Married: 11 Jan 1998, T: Since 1992 First Bomb: Sep 2007 Confirmed A/OM: 4 Nov 2007 Kids: D10, S5 Reconciled and together again after (alot of) time and heartbreak. 3rd kid, S, born 2 Jan 2010.