Puppy, Great thread. I too wish I had stayed away from the begging, pleading, and crying. Easier said than done though. I think the right solution would be DBing with a little tough love thrown in there. I think often, that we WAS are too afraid to set boundaries for the fear that we will push them away further.
Basically we are too afraid to tell them to stop seeing the OP for fear that we will push them away. Well, they have already pulled away so can we really push them further by telling them that we do not wish to be part of a triangle?
I'm just rambling here...please feel free to step in and agree or disagree.