Hey HWA.. You are growing every day, you are doing great. I too commend you for standing for your marriage. As far as the car is concerned, I think your W might need to feel what its going to be like if she has to start taking care of her own finances. I think at least you should ask her to pay half of the rego. That's not too harsh but at the same time you are saying to her, this is the start of your financial independence.
