I dont know what to do?

About Aug my wife started working a late or early shift at about the same time she started to become distant. It wasn't very apparent until recently just the past couple of weeks or so. That's when I started noticing some signs. She used to leave her phone on the kitchen counter, now it goes everywhere with her and she pword protected it. The new ringer on it is Bad Girlfriend. She used to hate the song Lips of an Angel w/ a pion now its one of her favorites. Shes been getting a lot of break up type songs. when her phone goes off she hits ignore when Im around. She comes to bed unless she sleeps on the couch like clock work @ 2 am, I confronted her about all this and she says its all in my head, now mind you she not sure if she wants to be with me or not. So I had to prove that it wasnt in my head and I downloaded a program that records chats IMs and pwords. She is busted not only is she IMing guys but she has a membership on on a cheating website Ashley something. Its like I dont even know her from what I read on those. I think one of the worst parts is shes talking a little dirty, but says things like I couldnt wait to get on line to talk I missed you oh and heres the worst calls one of them Lovey. I mean thats what she calls me. How are you just going to do that. I guess luckily none are in our area, however one of them said when I come there. Also we have a child and next month would be our 10 year anniverseary, been together for 13 years.This sucks Ive lost 20 pounds over this Im just not eating maybe like a lean cusine for dinner that I have to force myself to eat. This is just not healthy. I guess this turned into more of a session then a question anyway thanks.