Contrary to conventional thinking, the majority of partnered men in the United States lose economic status when their unions dissolve. Using data from the Panel Study of Income Dynamics, this analysis shows that for most men the primary source of economic decline after union dissolution is their inability to fully compensate for the loss of their partner's income. A secondary source of economic decline is an increase in compulsory and voluntary support payments. Welfare state tax and transfer mechanisms have a much smaller overall impact on changes in men's living standards following separation. Although most men experience a decline in living standards following union dissolution, men's outcomes are heterogeneous, and the minority of men who relied on their partners for less than one-fifth of pre-dissolution income typically gain from separation and divorce. The data show a clear trend toward greater economic interdependence in American partnerships, and this trend appears to increase the proportion of men who suffer a reduced standard of living following separation.