Let it be. I kept my married name. It's the same as my kids and it's the professional name I've used. In fact I had it almost as long as I'd had my maiden name when we got divorced. It shouldn't affect you in the slightest.
As for child support - you are contributing to their quality of life. Even with your contribution they will not be living in as affluent a household on either end, as what they had before the divorce. Kids are expensive and this is your obligation. If this helps them live in better housing, have more amenities, go to a better school district, afford a vacation with their mom - these are all things you should be supportive of. In extreme examples, for instance, it would be bad for the kids to live with one wealthy parent and then have to go half the time to live with a poverty-stricken parent in a slum. Child support helps ensure that their quality of life does not vary that greatly from one household to the next. Let go of the resentment, it will only hurt your children.
(My ex held on to his resentment over my alimony - our kids were grown. I'd mommy tracked my career in order to relieve my ex of all those pesky child-rearing issues that would have interfered with his surfing and mountain climbing and his great career success. If I'd had the support HE had, I could have had an equally lucrative career. But since someone needed to raise the kids, and breastfeeding and other issues made it most logical that this be me, and since I had some serious health issues possibly triggered by pregnancy, my career slowed down to part time in those years. I work full time now but make much less than my ex does. My alimony is by the book, actually less than what the formula would give me. But my cheapo ex thinks in his mind that since he pays me alimony after a 24 year marriage, I should be solely responsible for helping out adult children when they need help . Don't be that guy - he's losing his relationships with the kids over it. You made a commitment to the kids and this money benefits them directly or indirectly. )
