I haven't read your whole sitch, but if your wife is having an affair, there's absolutely no reason for you NOT to separate your finances. It's very typical for people who are wayward to drain family finances on their affair partner, or even on their own sense of entitlement.
You were wise to protect yourself, and I hope you'll continue to, and not apologize for it. "I can see why you'd be angry, but I'm doing what I think is best right now in order to protect myself" is all you need to say to her.
