stop asking yourself if she really wants to get divorced.
the way things are right now...why would she want to???
she can have pretty much everything she wants form you and the OM...until one of you presses for more there is no reason for her to file or change the status quo
any hope you have for saving yoru marriage should NOT come from her actions
she has checked out she is nice to you because it is easier for her
she could live this way forever can you Frank???
this is your journey one you may not have voluntarily started but one you are on
she is not your travel campanion just someone else whose journey happens to intersect yours every now and then