Child Support Issues

I don't know why it was so hard for my ex to actually believe that child support was necessary but when you split up, there are no longer two incomes in the household. Raising children is something that takes money, especially now days. Clothing and food expenses have really risen alot lately. Not to mention the gas to take them to and from outside activities, school and daycare. My ex cried around about the big $350 a month that the lawyer said I was due each month, so I was nice about things and lowered it to $275 a month. I honestly wished that I hadn't done that, but I did. I was in such a hurry to finalize our divorce that I settled for less than I should have. That amount of money doesn't buy much. She is a teen now, and the price of just her shoes are outrageous. Did he think that I was just going to pay for everything for her by myself? I didn't make the kind of money that he was making. It honestly takes two parents incomes to raise children. What was he thinking?