OMG, you just don't get it. You think that check you send pays for your child when the custodial parent has custody? That 30% of your income, or whatever she's entitled to in your state? That isn't even an inkling of what it costs to raise a child full-time even with the non-custodial parent getting the child weekends and in this day and age 1 day per week. I think Mitch got Heather for 1 month in the summer. Gimme a friggin' break. I worked a full-time job and worked as a bartender 2 nites a week to pay for Heather and I when I was first divorced.
I honestly don't wanna hear it. If your child is small, they need milk, and food, and diapers and a shots, and doctor visits and a TON of things. If you're child has started school, there are school books, school fees, school clothes, extra-curricular activies such as bein' on the volleyball, football, whatever team. School field trips. My list can go on and on. When they get to high school, then it really gets costly.
Again, as far this the child bein' with one parent for so many months and then the other, it's very hard on the child. BUT, there are some parents out there who do have joint custody of their children and it can be done. Again, take it to court. That is your option.