I'm going to go back to high school to help you see the friend thing a different way.
How many times have you or someone you've known liked a girl but gotten placed in the "friend zone"? When you're in the friend zone, yes, things are friendly and you have interaction, but you are not in the romantic position.
Consider this also: how is continued contact with WAW knowing she is coming to you after romance with OM affecting YOU? You can stand without having it rubbed in your face.
You don't have to be mean, but you can lovingly detach and do what's right for you. It's clear you need to DO SOMETHING DIFFERENT. The friend thing isn't working for you; it is normalizing her behavior. Right now she has her husband, the friend, and OM, the lover, and that's working for her. How's that working for you?
Since you can't change anyone but you, then YOU have to change something in your control.
SD
Me: 40 H: 43 H had EA from 2/06-9/06 Bomb 5/06 Piecing since 9/2006 3/2008: Boundary setting 7/2009: Boundary crossing~dropped my own bomb. 8/2010: Marriage finally on track!