How do i know if my wife is back home for the right reasons?

We have been together almost 10 years we have 3 boys together also. My story goes in march 2011 we had been fighting for a few day's she would start them over nothing and it was really bad when she was at work so things blow up one day and she wants a divorce ok so she leaves goes to the town she works in and gets a hotel room for three days also gets new bras shorts and gets all shaved up she said it was bc we didn't get along and that there was no other guys come to find out she was running around the second night with a guy from her work well yea they have sex three times and the first time was days after leaving home but she says she never left over the guy at work it was bc i was a butt to her so as time goes by she is sleeping with him but he does not want a relationship she goes after another guy but he ends up with someone else so now she has no guys to run after and a month of her being alone she starts calling and texting me saying she wants to b a better person she wants us to get back together blah blah blah so of course i love her so i let her come around and she tells me she wants us to work she loves me so on and so on she says she don't talk to either guys she was talking to she had said the same thing like a month ago and lied but we was only talking a month ago here is the situation she moved in with a female coworker she lost her car so she goes to work and back to her coworkers house i have a car a home ect she says its real feelings she has for me n wants to take things slow bc she wants us to work i have a hard time thinking she is being honest she has been saying stuff to me about us for weeks i looked on her phone yesterday 6-21-2011 and it shows where she was on the guy she was sleeping withs facebook looking at pics of him. I need help she has swore death on our childrens lives she was telling the truth and i found out she was lying Im trying to figure out if its a desperate thing on her part or is she really going to grow up Please if anyone can help or guide me in the right direction i dont want to b used then droped by her anymore thanks for ur time..