This is just my personal opinion, but I would go as low as the law will allow. If she needs additional help, you can still choose to give her more on the side. Don't lock yourself into a payment that you're going to resent later. How are you going to feel if you give her more and she starts dating someone else, long term, for example? I saw that happen once and it was SO hard for the ex-husband. What happens if you yourself fall into some financial difficulties? You also have grown kids to help her. You don't have to give more than the law demands. Again, just my personal opinion, especially given that she's the one asking for the divorce.