Now as far as the chance of there being a OM. Should I check? I mean, in her mindset she probably would think I'm stalking her. Does it even matter if she's seeing someone else?
At best it would substantiate lies, but also make me angry. It'll just hurt so much that it would piss me off and knowing MY track record I would probably run my mouth.
Knowing isn't going to hurt you but I definitely wouldn't advocate stalking her or anyone, that's just wrong.
Set her free, if she really wants out, let her go.
But view it as her loss, not yours.
That's the mindset.
If your marriage isn't worth it to her, why is it worth it to you? Let go of the people that don't value you or the relationship they have with you.
Allow her to make whatever mistakes she wants to make, you can't stop her even if you try.