I'm sorry you had to see those things. I know it hurts. This DOESN'T mean that this is her true feelings for you; it only means that it's her true feelings for you right now. She's still fogged out from her contact with OM.
Still, if this helps you pull back (and I do think you need to pull WAY back), this can be a positive thing. We still haven't seen what your wife will do when she ONLY gets cake from the OM, and no longer has any of her other emotional needs met by you. From your descriptions of your wife's moods, I still think she won't handle that well, and will realize what she had in you, and want to come back to you.
Whether she can do that before you lose what's left of your love for her, remains to be seen.
Let her eat but ONE kind of cake for awhile. I'm not so sure she's going to like the taste of it.