Using a large administrative panel dataset from Germany, we study the effect of a divorce law reform on the probability to pay alimony as a divorced father. The reform affected divorced couples differently depending on the age of their youngest common child. Using a difference-in-differences setup, we show that the reform decreased the probability to pay alimony if the youngest common child was between four and eight years old compared to the child being between sixteen and seventeen. Therefore, the reform decreased the disposable income of divorced, single mothers with younger children to a greater extent. Our results are robust to different empirical model and control group specifications. They also persist when we restrict the sample to those couples who got divorced before the reform. Furthermore, we show that the treatment intensity of the reform varies with the age of the youngest child having the largest impact if the child is between four and five.