I think there are short-term, immediate boundaries, and then there are long-term, things that you will abide and that you won't.
"I will not live in an open marriage, or one where my wife is in contact with OM" is really more of a LONG-term thing. Even kicking her ass out, and going thru a contested divorce, would take time.
Short-term boundaries should be things like "I will not tolerate your texting OM from inside of my own home," or " . . . in front of me or our son." If she's doing this from elsewhere, there's not much you can do about it other than proceed with your own plans about the marriage, or to set your own deadline (maybe 3-6 mos., or whatever you feel you can endure).
For me, my short-term boundaries were:
- no texting or phoning OM from inside of our home;
- no texting or phoning OM in front of the kids, regardless of where you are;
- if you're going to stay out past 1am, don't bother coming home;
- I will not allow family's finances to be used to enable your affair (cellphone, tummy tuck Visa payments, lingerie, haircoloring, etc.).
And then yes, I also stated my overarching boundary of "I will not live in an open marriage," but I gave her no deadline on that, nor would I recommend that. Because if you give them a deadline of, say, Dec. 1st, then they'll cake-eat until Nov. 30th, and then promise you the moon and the stars at the 23rd hour to try to stave up you dumping them.
I think you need to separate what your immediate boundaries are, from your overarching one.
