when you say 50% percent of the nights, do you mean you are splitting custody? Do you have shared custody? i don't know anything about Texas, but couldnt you modify for shared custody?
As far as financially supporting the child, like I said they do make allowances for the custodial parent, and the extra burden living in the home puts on them. As i stated in my states example they will minus 15000.00 and all daycare and ins. costs from the CP income BEFORE figuring the NCP's child support figure. This is of course only in the 'traditional" joint legal, physical custody with one parent arrangements. In cases of shared physical custody the burden is more evenly split between parties.
now i thankfully, have a husband who's ex, though a real "winner" does work at a decent job besides receiving support. so a bit of her income does get counted. but even if it wasnt (and really it doesnt as she only makes over the 15000.00), or she sat on her butt, I look at it this way...
We don't feel guilty or mad at what she decides to do with her money, we pay a nice amount of support in full and on time every month. If she chose to live on just that amount and 'live" off of us, more power to her! I would want to know her secrets- I know we couldnt live of that amount and would get really bored pretty fast!(and be homeless OR hungry OR carless to boot!) And being as my husband already pays the full legal amount of support she couldnt get any more out of him for us to even worry about. (kind of like "oh you can't make it on support only? well hand em over!" put a stop to THAT in a hurry I tell ya!) Our 50% is financial her 50% is using and contributing to our 50% for the roof over thier heads, including food and clothing etc....
As far as shoe being on the other foot, unless my husband suffered a huge cutback (and he has in the past for a long enough period where he was granted a deduction, he now pays 2/3 of what the original order was, which made ex mad, but he proved his income was steady at that correct rate even when he was paying too much) we are always going to be paying what we are paying, it goes out of the house first just like taxes LOL! not part of my budget at all in our house it is income after support not income after taxes! If my husband wanted to go back to school, he would have to do it in a way that we could afford all our debt....