I have no sympathy for a guy who resents paying child support. Tough ****. Get over it. That's a right your child has, not your ex. A father paying his child support will never have to make excuses. And his child will, when he grows up, judge him by whether or not he paid it. Perhaps he will forgive him for not paying it; but it will always be in the back of his mind that his father abandoned him monetarily.
When a guy has another woman in his life, more than likely she resents those payments going out of her household, and possibly her children into the hands of "that bitch." Don't listen. Work harder. Or kick her to the curb. That's your child. He deserves your support. He didn't pick his parents. You guys did.
Why are there deadbeat dads? Probably because they were jerks to start with. I've seen guys go completely off the grid before they'd send that bitch a cent. Almost ruin their lives. Pick an entire lifestyle designed to make it impossible for his child's mother to get help. Jerks, every one of them.
(I'm not talking about you, Oscar; it's just more conversational to use the pronoun.)