Maybe think about separating some of the expenses. Like her car payment if she has one, or her phone bill, credit cards, etc. Your money for the family expenses only. No reason you should support things that are detrimental to the family. It's not a tactic, it's about protecting yourself.
Remember don't ask, just do. If you do discuss it with her ahead of time only discuss the "how" or "when" it will happen so she knows it's coming, not what she thinks about it. If she doesn't like it that is her problem. Consequences of a WAW without talking about D.
Me:49 W:45 M:19 T:22 EA confirmed and ended 8/2014 S:19,17 D:9,5