Just work on yourself and forget about your wife and OM.
I understand that's really hard to do, but the sooner you start detaching the better this will be for you.
I know you don't want to hear that your wife's relationship with OM *could* be physical. No one wants to know that about their spouse. Believe me, I didn't want to think that about my husband and he's the last guy I'd ever suspect (and also OW did an amazing job of convincing the husband she loves so deeply that nothing happened-- even though I later learned it did. My husband was so ashamed....). Anyhow, I've learned that when it comes to affairs there is often much more going on than you realize. Hopefully you are correct, but based on what you've described, just be prepared in case there is. Please read some books on this so you can understand it better -- even if it's only emotional. I found "Not 'Just Friends'" very useful in understanding how affairs can occur. This helped me understand how easy it is for anyone (even in great marriages) to get involved in affairs. It also helped me not take the whole thing so personally. Often it isn't you, but problems that a cheating spouse has (like boundaries!).
Anyhow, please start reading, start learning about affairs and begin working on yourself. I want you to know this isn't necessarily a bad thing... sometimes it's challenges and negative situations that bring the most insight and growth.
There is no arriving, ever. It is all a continual becoming.
