nit84, I would talk to a lawyer. You don't have to do anything with the information you get, but it's good to have it.
If you suspect that W is manipulating you, then decide for yourself what you want to do about that. Your best bet may be to assume the best until you get burned (assuming the consequences aren't too dear). If you get burned, then make a different decision next time.
In terms of letting her know you're not okay with the sitch, I'm sure she knows that.
When you say you don't want her to come back just for money, think that through. Pretend she DID come back and agree to work on the marriage, but that money was her motivation.
You can prepare for that. Think about what YOUR requirements are for her to return to the marriage. It might be attending Retrovaille together, going to MC together, talking to a DB coach together, there's probably a list of things you would want her to do, and behaviors you would want to be a part of your *new* relationship.
If you set up your return requirements right, then it won't really matter what her initial motivation is -- if she takes the first step, she takes the first step. If the help you get is good, she may find the motivation to run the whole program, and then you won't care why she started. Either that or she'll wash out because the money won't be worth the work she has to do. Either way your integrity is intact.
Acc
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015