No, whether or not your ex-spouse gets remarried should not affect what he has to pay you. However, if your ex had additional children with his new wife, he could ask for the court to order his child support obligation, and the court may agree, since he would have additional children to support financially.
On the other hand, if you were to get remarried, it’s likely that your alimony would stop and your child support could possibly be readjusted. Typically, alimony ends upon the receiving spouse’s remarriage. Child support is based upon the income of the parents, and if one parent gets remarried, child support may be readjusted due to a change in the household income.
In order for child support to be modified, your ex would need to go to court. In court, he would have to prove that you will have more income after the marriage, and the judge would have to agree to modify your child support. If that happens, you can present a strong case about why child support should not be modified because of your remarriage. You could show that you and your fiancé plan on keeping your finances separate, or that your income after expenses will not be affected that much by the remarriage.