She said during one of our fights a little while ago that she thought that I would not have a problem, given our current troubles, if she dated other people after I returned but was waiting to until the Army let me move out towards the family.
She was gauging your reaction ... and *hoping* that you would roll over and play dead. She's already actively involved with OM ... at least emotionally ... and she's looking for "permission" from you, her H, so that she can justify what she has already done.
She's lost it, dude. She's an alien right now. It doesn't make sense to us, thank gawd, because we're thinking logically ... and we don't understand illogical behavior. If you sit around right now and try to analyze everything she's doing -- and why she's doing it -- you'll drive yourself crazy.
And that's the reason you gotta do whatever you gotta do for *you*.
Here's the "nut" question that I've always asked anyone in your shoes:
If the way she's being right now is the way she's gonna be, can you live with her? Can you stay married to her? If not, then what do you have to lose by growing a little backbone and telling her you won't tolerate it?
*Worst-case scenario*: You tell her you won't tolerate it, and she tells you to take a hike.
How much worse is that than what you're dealing with right now? It's really not that much different at all, IMHO.
Do what you have to do *for you*. What can you tolerate? What can't you compromise on?