Living with that knowledge is hard. I can appreciate how you feel. What to do next is a deeply personal and complex decision that only you can answer. You have to live it and live with it for years to come. I was married for 18 years and when I found out my spouse had cheated I knew it was over right there. There are spouses which have cheated and the relationship bounce back, too.

Best advice I can say is to take a step back, compartmentalize your situation the best you can and determine what is right for you. The next step would be initiate the conversation with her if you can. If you don't think it will be amicable, find a counselor or therapist to help you both. But if you think that either or both of you want to split up, CONTACT AN ATTORNEY! You have children together and at the very least you can draw up an agreement between you both on how to co-parent. Just my thoughts, not a sermon. Best of luck my friend

If what I suspect of your loved one to be is true then on the face of it she has cheated on you, technically though no so.

Being legitimately cheated upon is an almost impossible thing to deal with with regards to the relationship healthily prospering, such has been my experience anyway, I forgave, I was simply unable to forget though (and as it turned out it was a huge mistake doing so, because at the time she supposedly cheated on me, she was being raped instead of).

At times all is not what it seems to be. Right now champ your focus is on the negatives, you are shortsighted, you have blinkers on, take them off and, a bigger picture will emerge (take your emotions and your uneducated preconceived judgments out of the equation - smart people are open minded people, you strike me as being a smart person). Focus on why her instead of why me.

Stay.
We all need to work on our charity to our most loved ones.
She'll probably have to do the same for you sooner or later.
You two have a shared responsibility to your children now and to each other. Welcome to the club.

Take time to really think and if you really love her, then see if you're willing to work it out.. it's not easy, and you must forgive, it's extremely difficult, and then you must move forward... Trust has to be rebuilt... No one but you can know if you're capable of moving forward..best of luck...

I do love her... and I want to stay.. but she won't admitt to it... that's the hardest part.. if she would just talk to me we could work through it.. I'm willing to forgive, I'm ready to forgive... I just need her to come clean and stop...

Petemason, I have researched the web... I realize some of this is my fault... but not all... this is hard... I'm super stressed... I can walk but I don't want to.. not yet...

Cheating is not your fault...period. Cheaters use this excuse to blame the spouse for their selfish actions. Not your fault she chose to sleep with someone else.
Problems can be worked out if both people communicate and talk out their problems. A third party can help example therapist.
Not having sex with someone else...that does nothing but serve a selfish need.