I'm almost always wrong about the adultery stuff but being someone who is pretty much in your wife's shoes at the moment I think that it is entirely possible that there is no particular man in whom she is interested. The thing is if you are a reasonably attractive HD woman who has been in a SSM pretty much the minute you turn off your "I AM MARRIED" vibe or protective shield you start getting the vibe of interest from other men. At the moment, your wife has every reason to feel confident that her odds of having a decent sex life in the future if she leaves you are much better than her odds if she tries to work it out.
Also, it's entirely possible that the reason she is being "nice" at the moment is that she has completely written you off as a sexual being. You are like some Ken doll in her mind. No reason to be angry at you but no reason to be sexually attracted either. IMO the best thing you could do since I don't think that you will have much luck approaching her physically is to write her or e-mail her or even call her on the phone and let her know in detail all the sexual activity you have planned for your new future together. The reason I say this is that although there are other issues involved in my separation that make me more than loath to consider reconciliation, the negative thoughts that I have around the issue of sexuality in terms of reconciliation are along the lines of "If I were to reconcile with this man I would never, ever, ever have sex 3x in the same weekend and I would never, ever, ever get fantasy A or B fulfilled. Etc. Etc. Etc.". When you are still in the thick of a relationship, as opposed to halfway out the door, it is easier to write off these kinds of desires as just the sort of thing you might be willing to do without or compromise in order to maintain the relationship. Once you're out, or halfway out, of the relationship, these sorts of things seem fairly easily obtainable and you really wonder at yourself that you were willing to do without.
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver