I think, personally, that you are focusing way too much on the affair, or non-affair, or whatever it is. It's distracting you from even looking at what you can do for you. Yes, Puppy does advocate affair-busting, but even he says there is a time for it. And not everyone agrees that it is always the best thing to do. For him, it worked. But there is no guarantee.
You say you set a boundary. But a boundary is only going to be effective if you are willing to back it up, and if the other person is interested in respecting it. In your case, you are not ready to back it up, and she is not interested in respecting it. So it ends up being a threat with no teeth, that only ends up making you look weak.
From here, it looks like she knows she can mess with you, and she is taking full advantage. And you are biting; hook, line, and sinker.
