So they have a "new toy" which is exciting to play with. And they're discovering their "old toy" is fun to play with too.
When a person has the comfort of being able to make a choice and isn't forced to make a choice immediately, what would motivate the WAS to make a choice at all?
I agree completely Robx, with one distinction.
The idea is that the WAS has to believe that they are in danger of losing LBS, that LBS is valuable, and that they (WAS) has to make a choice.
Dating is one way to do this. It is a simple and direct way, but it is not the only way, and it has it's own dangers and entanglements. It is also only really possible for those LBS's who are separated, already D'd, etc.
This is why DB places emphasis on being busy, being somewhat mysterious, and being unavailable. This shows that the LBS is valuable (interesting, busy, unavailable), and helps WAS see that they may be losing LBS (Unavailable, mysterious, so what is he or she doing anyway...?) LBS also needs to conquer his or her own fear of D so that he/she can firmly set boundaries and be ready to enforce them - also showing that WAS may be about to lose LBS.
I don't have anything against Dating itself, but I do know myself. The moment I start dating / sleeping with another woman would be the moment I have given up on my M, because I know that I would immediately become emotionally entangled with the new woman.
Me 42, W 39, S8, S6, S2 M 11y, A & ILYBNILWY 11/08 Walking away from a bad situation.