Like i tell my buddies, condoms are so much cheaper but anyway...
What you pay her should be court ordered and is based on your pay. Also do you have shared custody ? Do you want full ? Then you wouldn't pay $hit. For your sake (in/out court) keep records OF EVERYTHING you give her. I don't care if its a f***king stick of gum, write down the date and time. Im sure you are already away never pay in cash.