Alright COG... let's get down to the straight goods...
You are confident there's an OM, but you don't want to confront W.
We find that confronting the WAS will always lead to... well... lies...
It will be said around here with regards to WASs, especially with EA/PA... believe none of what you hear and only 50% of what you see.
My W's OM is about 10+ years younger than her. I do not know the status at any given time, although it appears to be light and possibly infrequent... getting her "fix" as it were, now and them... I don't know, but suspect when the WAS goes after significantly younger OPs, it is probably more fulfilling... they feel young and invigorated... I'm just guessing...
You'll hear around here that an OP/EA/PA is like a drug to a WAS. There's no way to know how long it might take for her to kick the habit... if she does at all...
Everything else is pretty much said this way... you'll need to pull up your britches and start concerning yourself with YOU.
If you want ANY hope of getting through this a better man (and that's the goal, regardless if the M is saved), you need to start working on YOU.
Without it being your goal, becoming a significantly better YOU in ways that STICK (permanent betterment) might be attractive to your W and she may seek you over OP.
Another thing you'll hear around here is:
Become the man only a fool would leave...
So GAL, try some 180s, and be strong... what are some GAL activities or 180s you might consider doing?