First of all - I don't know that this is really a "boundary" issue, at least the way the term is used here. Usually when we talk about boundaries here- it's in regard to how we allow people to treat us. That's not really the same thing as "I don't want you to expose our kids to your AP". Others may see it differently.
Second- your wife and all the WASs on this board have lost all reason on this topic. It doesn't matter that there is a mountain of easily available data that points out how bad it is for kids. It doesn't matter that their own friends and family think its a terrible idea. It doesn't matter that once upon a time they themselves thought it was horrible when someone they knew did it. You can call it "affair fog" - but they have crossed a line and no longer think rationally on this one.
Third - this board is littered with people who agonized over this same problem. Some of them had very strong voices and confidently asserted that there was no way their WAS would do that. Guess What? They almost always find out that no matter what oaths were sworn, the WAS did whatever the heck they wanted to do anyway. I've been reading these boards for 9 months now. I can tell you it happens over and over and over and over.
In my case - the first time I saw my STBX after he basically ran off - I was very amenable to most things- but I made it clear that he was not to bring my children around his girlfriend. I believe the phrasing I used was "That is the one thing that will make this situation incendiary". He agreed emphatically that he wouldn't do that. But of course, he was already secretly living with her and introduced them that very weekend.
I had some suspicions for a while that he denied with righteous indignation. When it finally came out two months later, I have to say that it was a deal breaker for me. I began to completely cooperate and even drive the divorce.
Now she gives my daughters massages. Not a thing I can do about it.
My only hope here is that he might eventually lose this girlfriend and then I might be able to have a conversation about the advisability of introducing kids to romantic interests too soon, while he is somewhat sane and rational.
Sorry to be a downer, RAI. Can you stop it? Maybe if there is some consequence that she cares about.
