Hey F4WR,
Welcome to Marriage Builders - we're sorry you're here and glad that you're here! You are in the right place. You've been reading a lot on the site, that's good. It has helped many many people.
Do you have children with her? How long have you been married? How long has the A been going on?
It is not too late to Plan A. Definitely too early for Plan B.
Have you read, "Surviving an Affair" by Willard Harley or "When the One You Love Wants to Leave" by somebody Harvey, and "Love Must Be Tough" by Dr. James Dobson?
Any or all of these books will prove to be a tangible reference guide of what is going on here and what you need to DO to stand the best chance of getting your WW back and saving your M.
You do need to have the confidence and respect to put forward with your words and actions that you love your wife, you want to work on fixing the marriage, but that you cannot and will not tolerate being in a love triangle. There is nothing to counsel about in marital counseling until the A is ended. You may want to see an individual counselor or pastor at this point.
Your wayward wife is in the fog, not thinking clearly, and is rationalizing her behavior. BUT, what have your LoveBuster's been (other than angry outbursts - which is huge). What are her emotional needs that are not being met? How much real quality time do the two of you spend together (well, before the A)? Are there any other issues that are relevant on either or both of your parts - alcohol use, porn, gambling, past s*xual abuse, drugs, spending/money problems, religious differences, family problems, you work too much she works too much, etc??
Of course, NONE of these justify her affair, but the background can be helpful as far as what you need to work on in Plan A.
Best wishes, you will be in our prayers and keep posting.
NTL