I was just reading through InPassings post and I don't want you to think I was trying to get you too push ahead the divorce. I would let her take the reins on that, just make sure you have the saddle cinched for the ride.
I don't know about paying for the lawyer with a credit card. First, your wife might pick up on it. Granted she may already being seeing one, but usually the WAW spouse initially see's this action as a hostile act. It isn't a bad thing for a WAW to know about it in some situations, but I don't think you are ready for those actions yet. Second, and to me the bigger one, is that she has noted your credit card abuse in the past. Whether she is right or wrong, it is what she thinks and feels. Your use of the credit card could be seen as a slide back to your old habits..I know it is tough with this economy, but find another way.