For some reason, I don't see this convo as inappropriate or bad DB at all. I think at a certain point in a sitch, probably where yours is now, it may be as important to be able to have these talks and NOT have them turn into fights, i.e. validate and express SOME level of understanding, than it is to avoid them altogether.
Overall, based on what you posted, you did fine. I am more confused than ever at her apparent openness about these decisions she is making, and her idea that they don't change things, but whatever, WAS don't make a whole lot of sense most of the time.
I think you are doing fine. You're taking the MUCH harder road, but to those who say you're crazy for taking it, I say both roads, laying down the "law" or riding this trip out both COULD lead to the same places, either the end of your M, or reconciliation. I think you and I happen to believe that whatever the case, reconciliation based on her freely chosen decision to return to the marriage, rather than something "forced" on her by you, will result in a deeper, stronger and probably longer lasting marriage.
You have to do right by you, based on what you want, and can handle. I think you are doing just that and I love your PMA at the end. When is this trip? I'll try to be on more then to make sure I can help in any way.