Being a woman, I think you should've handled it more softly. I would not have responded well to your approach. But, Starsky is great on this stuff so I generally defer to him. I guess it depends ultimately on what you want right now, more secure finances or a more secure W. I get the bind your in though. It does not seem like you can have both at the moment. Sorry if I was too harsh. I'm with you ultimately and support your efforts. . .
Unbidden, it really ALL depends on what stage Zew is in, and what his goal is at this point. If there was no infidelity here, and his wife was "just" a WAW, I would tend to agree with you. But a continued, deceitful affair -- and then you fold in her financial/debt issues?
I think the strong boundaries and even him "controlling" the finances are NEEDED here. Acknowledging that short term, it may push her away a bit. I think longer-term she will respect it (which is attractive), and he will also be protecting himself (and his children) financially, so I consider that the "greater good" here I guess.