That explains a little. Complete NC is not practical in this case. However, discussion between your H and the OW that involves his personal business -- you Yoyo, my dear -- should be off limits at the very least. Any discussion about you and H's relationship with you is just wrong. H should tell his employee that if she ever says anything again to him that is so inappropriate for them to discuss or is just plain none of her business, he should threaten to have her written up and that placed in her HR file.
But I guess he doesn't have the b*ll's to take that strong a stand yet, does he?
So is it that he's trying to hide that he might be truly backsliding, or that he's afraid of giving you that impression?