Absolutely not.  Your income doesn't get considered, in setting his child support (other than possibly determining how much his child support to the ex is affected by the need to support a child or children he has with you, and only for that reason).  And his ex has no claim on your paycheck, or any money in an account that's only in your name.

If you husband loses his job, he needs to do two things:  one, file a motion with the court to reduce his child support after the first month of unemployment, if he doesn't have a new job, or if he takes a job at lower pay.  Two, he needs to keep very detailed records of his job search, because he will need to prove that he's made finding work a very real "job" that he takes seriously, before he'll be allowed to use his unemployment as a reason to reduce child support.