Oh, I forgot to add.. If you're going to expose, first get proof, then take your WW stuff out of the bedroom, when she asks why, calmly state that you will not share your marital bed with cheater, that you will not be in an open M and she can find somewhere else to sleep.
Do not "talk about it".. Do not be mean, just tell her you will not be part of an open M, nothing else. Do NOT tell her you are still willing to work on M, just leave the house for awhile. You want her to think she's lost you, you want her wondering what your thinking. Just completely leave her in the dark. If your accusatory, mean or spiteful it will hurt your chances of getting her back... Just leave the house (don't tell her your going to contact OM W either).
Then message OM W with your proof.
M - 9 1/2 years 5/5/16 - Bomb drop - 3 week EA 10/31/16 - We sold house 01/10/18 - D Finalized