Jld's approach is really solid, once she's out of the affair. MC is worthless when someone is in an active affair.
. You can't compete with the high of a new, illicit relationship. You are basically dealing with an addict, and begging, reasoning, will only work against you.
You don't want to file D, but you need to fight for the marriage. Something between the nuclear option and degrading yourself is called for.
1. Investigate. Check out @weightlifter
s standard evidence thread. Find out who the OM is.
2. Apologize once
for your contributions to the marital problems. Do not let her blame you in any way for her decision to destroy the M and family.
3. Expose to family and close friends. Not in a vindictive way, but asking for help and support. She will be furious and tell you that there is no chance for R now. This is important, it will kill the fun of the new relationship.
4. Expose to the POSOM's wife if he's married. If he's not, expose to his family.
5. Look into the 180 and live it. It will help you keep your sanity.
6. Lift weights. A lot.
7. See a lawyer to understand your rights.
8. Get a VAR (voice activated recorder). She may try to accuse you of domestic violence and have you removed. Our society will take her word over yours. She'll be a victim, you'll be a monster. Even if it's illegal in your state, better to have that evidence and protect yourself.
9. Don't tell her any of this before you do it.