My original plan was to confront her in a way she can't deny it. I was going to be at that same spot where she stops and find out exactly what's going on.
I wouldn't do that, it can force a really ugly confrontation that can even result in physical harm. I just picture you trying to calmly discuss it with her and her screaming at you and OM running out of the house and things spiraling out of control from there.
Here's the deal, OM is not the cause of the marital problems. OM is a symptom. If you're going to push for S or D with your W then you don't even need to bring up OM at all. She has engaged in EA's in the past, she refuses to work on the M, you're in a sexless, loveless M by your W's choice and she therefore has violated the M covenants. That's enough to justify your desire for S or D without even bringing up OM.
I am of course not condoning S or D, DB'ing is all about trying to save the M. I'm just saying that if you want to pursue that then I don't think you should force an ugly curb-side confrontation.
