You did not have to give him the money. He got himself into this situation. He probably agreed to it because he knew you would bail him out. This is his problem, not yours. Maybe it is time that you thought about your boundaries and what you are and are not willing to do. Then, you can talk to him calmly about your boundaries. Maybe your boundary will be that you will not give him money to help his ex-wife. Then, stick with that boundary. He is a grown man, and he can make his own decisions and take care of himself.