I suggest that you and your husband separate yourselves from her and HER husband, for the good of your marriage. At least for a period of time until you can rebuild your trust and are fully reconciled.
That's a hard-core position, I realize. I also think it's the right one.
Puppy
M25,
I'm sorry to hear you're still struggling. Is this the same woman we spoke about before?
This is why I am such a "nazi" on no-contact/transparency plans. Without one in place, your H was destined to just get back together with her.