I don't know what your relationship with your metamour is like but it seems like it's gotten to a point where there needs to be more communication between you and her separate from your S/O, as well as communication between the three of you. For me personally the whole relaying what she says from him to you makes it harder for either of you to feel comfortable.
His wife might feel tense about the connection you two have, except she hasn't exactly voiced her discomfort. It has just become apparent physically.
I wonder when he is going to sit down with her and hash this whole thing out. I don't think she's necessarily against you; she might feel that you're in the way though, since there's a lot they need to work through as a couple.