She doesn't get to choose if she pays child support or not -- it's a state formula. The only way she wouldn't pay child support would be if she had 100% custody assuming she's the higher earner.
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015