First - clarify your goals for this encounter. As for the money issue - I think I'vealready asked but forgotten theanswer - is he currently paying more or less than the courts would make him pay in a divorce? If the lesser amount is less than the courts would dictate, then it might be worthwhile to point that out to him.
Maybe if you just filled him in on more details about ways you have considered to increase your income he would soften a bit? Or maybe for now you should just VALIDATE (I understand it is a burden supporting two households") and ask to discuss it at another time when D isn't around - you don't want to spoil her birthday by getting into money discussions.
Then - have the best PMA you can muster. Slip a card into your pocket with DBing notes that you can peek at whenever you need reminding - "validate, 180s, PMA, will this get you closer to your goal?, "etc. Then look sexy as heck and let him see your thong peeking out
