Wife just told me doesn't want to be married

[witz10]

Thank you MrBond for putting things in perspective. I have been at this uphill battle since May 1 when I moved out. I have done everything that she has asked me to do. From couples therapy to my own therapy to moving out. All for the sake of fixing our marriage. YES I WANT MY WIFE BACK.
I have read DB as well as Good Husband Great Marriage and Getting the Love you want a guide for couples. I asked for this one from my wife. I have worked damn hard on changing and going back to the way I was before we moved to where we are now. I see my mistakes and I know what I need to do to fix what was wrong. I need her to realize this and see I am trying. But how can she do this if there is another guy there all the time and she is with him when the kids are not around.
How do I get over this picture in my mind?
These past 6 months have changed both of us but I can still see the woman I married in some of the photos I have taken at parties.

It feels like am fighting a one sided battle and I am losing. Is there a turning point? She is not filing so to me does she want to work this out if so ditch the trash. I don't know and that is the hard part. Yes my self esteem is in the tubes right now. The woman/mother of my children is in another mans bed and I am alone with my thoughts.

I would be happy to take any and all advise on how to proceed.
Weekends I don't have my kids I go out with friends to take my mind off this. Week days I don't have kids I go to the gym and lost 13pounds in 6 months. I am looking for another job to get away from family. What else is there for me to do? I honestly don't know. Yes I want my wife back and she knows I love her deeply.
To add insult to injury her birthday is next week over the holiday and she offered me the kids the whole weekend. This was before I figured out she was seeing this loser. So she has plans for her bday weekend. This is the first time in 12 years I will not be with her. What do I do with the presents I have for her from me and kids. Also the flowers I planned on picking up.

This is my life now and I hate it at this juncture.

M37 W34
S6
D3
M8yrs
S6.5months