Any chance your husband can transfer? How much contact do they have at work?
I'm wondering how she would have reacted if you had responded on the text messages and said something like, "___ and I are having a fabulous time! Thanks for your thoughts..." In otherwords... acting like she was YOUR friend too... and also, letting her know you see her messages... that they aren't secret. That may help deflate things a little. Once the secrecy is gone the excitement usually tones down......
Unfortunately, seeing you as an advisary might make her work harder at trying to win your H over. And she might think, "Wow she really is a bit@h, no wonder he wants to leave her...." This makes it easier to validate to herself what she's doing.
There is no arriving, ever. It is all a continual becoming.
