Did you ALREADY separate the finances, and you just now told her that you did, or did you announce that you were GOING to?
If the latter, then I suggest you move quickly. You should never pre-announce this, as someone who is as deep in entitlement as your wife is right now is liable to drain your accounts.
That $500/mo. that you are subsidizing is going to be as much of a "drug" to her as her affair is -- if not more.
