You are a sweetie....and you hang in there doing the DBing. I am proud of you not giving in to the temptation of the young woman. I know it had to have been hard being away from your W and missing the sex, etc. But, I know you are still very much in love with your W and I hope that you can control that type of temptation b/c I would be leary of "rebound" relationships. To some people it would just be a one night stand.....but then you never know what is going through the OP's mind. Ever watch Fatal Attraction? (lol) Well, that was a little over the top to use that for an example, but you just have to be careful when you mess with people intimately.
As far as your W asking if you had a GF yet....and you wondered why? I can tell ya...since you asked (lol). Could be curiosity...plain and simple, however, I think it is a very good sign. Now listen to me sweetie...you guys get all pumped up over the least bit of encouragement...so I don't want you to go crazy here, ok? But, if she did not "care"....believe me, she would not have asked. The downside of that would be that she thinks you having a GF will let her off the hook (b/c you would loose interest in her) and get you out of her life for good. Hopefully, it is not that.
About the time slot for DBing, etc., don't even think about that....except to keep you from expecting too much too soon. I have also heard that there is a mimimum of three years in MLC...but I don't think that is true for everyone. When we realize what we are doing and really....really try hard to pull out of it, I believe we can. I also think I was sort of the exception since I was already over the hill of midlife....lol. I have to joke around and try to lighten things up a bit on here or this board would just get too depressing! Anyway, every couple and each individual is their own stitch and we can't measure it by a calendar. I have also heard some LBS say that if their S is not back in six months (or however long) they are forgetting them, etc. You just can't put a time allowance on relationships....not if they truly are important to you. But, I think you asked b/c you are in pain and are hoping that some mile markers have been passed. (((hug)))
One other thought about your W asking about a GF.....she may be watching to see if you go running after the women to satisfy your "needs" as she must have assumed you would. Maybe she thought she was just there to do that "service" for you. That sounds so harsh to word it like that, but some wives do think that is the only interest their H's have in them. Hopefully, she will see that you not are interested in other women for sex (or any other reason) b/c you still love her. Maybe that can help you to remember that when a "young thing" comes tempting you again.....and be prepared, cause it will probably happen.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!