My wife continually spends more than I make, what can I do?
Usually discussions about money take place during times when there is a surprise on a credit card bill, or items are discovered that were not bought in agreement. That is not the time to have a talk about money. Those times usually lead into an argument. Timing matters. Pick a time when both of you are in pretty good spirits and simply say, "Honey, I wonder if we can look at some new ways to handle our money". Then be prepared to invite her to a better way. I recommend Dave Ramsey's book, "Total Money Make-Over" as a wonderful book to teach people how to manage money, including over-spending.
I would also look at some things that might be inviting your wife to over spend. Are the reigns too tight? Meaning, does she have money that she gets to spend anyway she likes? Is she involved in the bill paying or being kept in the dark? People can take on a childlike role (over spending) if they think there is an endless supply of money. She needs to be involved in the total picture. Does she know how her over spending affects you? This is important to let her know when things are not heated. Let her know how discouraging it is for you and the stress it causes you.
Issues over money are the leading cause of divorce. So you really want to come into agreement about this as soon as possible. Ask your self if there are other areas in your marriage that are out of balance as well. Usually "issues about money" are symptoms of underlying issues which need to be resolved.