Yes. If your "ex" remarries your children remain your children unless/until someone agrees to adopt them.

Of course, the kids are still yours, if you are paying alimony it may or may not end.

But you keep paying child support ( on your kids) till the end of the state ordered period.

Yes, you are still legally obligated to pay child support regardless of how many times your ex gets married. Only alimony ceases when the other party gets married. You must be thinking alimony and not child support.

If you want to stop paying child support suggest to your ex that her new husband adopt the kids then you are off the hook financially.