Cody,
Calmly summon your inner strength. Maybe mix it with a little anger. You should be angry that she was not mature enough to come to you and verbalize her marriage issues well before engaging in her affairs. Yes, affairs.
Your goal here should be to move out of infidelity, not to try save the marriage. Maybe the marriage will be saved, and maybe you'll divorce. However, in order to have any chance at saving it, you must be willing to lose it.
Take the next few days off work. Do not tell your, wife. You're probably not in any condition to work anyway. If your boss asks why, be honest. Most are understanding of this situation. Use this time to do the following:
1. Split any money you have in joint accounts, open up a new account at a new bank, place your money there, and switch your paycheck to the new account;
2. Close any joint credit cards, and open one in your name;
3. Research divorce attorneys in your area, and visit a few this week to gain some insight into divorce and block her from using them in the event you do divorce, plus get some paperwork prepared;
4. Prepare and send an exposure letter to your parents, her parents, and your children (if age appropriate) informing them that although your wife hasn't informed you that there are marriage problems until recently, your wife has been having multiple affairs, wants to leave you, and you aren't going to stop her; and
5. Buy her a bus ticket to her AP's hometown, pack her a bag, and take her to the station, and tell her to go.
Right now she is trying to one-up you by telling you she has had multiple affairs, and is going to go to one of them. Call her on it. Drop a nuclear bomb on top of her conventional weaponary she threw at you.
You may balk at doing the above. Look at it this way. If she is truly done and is leaving, then doing the above will have to be done anyway. So, doing these things now will shorten the amount of time you have to experience in infidelity. On the other hand, doing the above may knock her out the fog, or make her rethink her position.
The worst thing you can do right now is nothing. You must start moving yourself out of infidelity. You may reconcile, or you may divorce, but you need to move out of infidelity right now.
Oh, and stop the marriage counseling and retreats. These are useless when your spouse is still actively engaged in the fantasy of the affair.