YES, I think splitting the finances. She's already dropped the D-bomb, so all you're doing is protecting your interests, and "moving on," both of which are good advice. If she tries to say YOU are pushing this, you say "No, I'm not the one who wants a divorce; I'm only protecting my and daughter's interests, and trying to move forward considering the decisions you're making."
I'd recommend splitting the joint family finances (minus ANYTHING she's using to directly or indirectly finance her waywardness, like cellphone, etc.) in proportion to your incomes. Any family court judge is going to direct you to continue to pay for "the lifestyle to which she is accustomed," so long as it's within your financial ability to do so, so "allow(ing) me to spend my money on D and I only" is not realistic.
