My divorce is final but my ex keeps saying he will take me to court for alimony. Can he do that after he waived it for the actual divorce?
NO. He had 10 days to appeal the final judgment. Afterwards unless you withheld information that would have been fraud on the court, there is nothing more he can do now.
The paperwork needs to be reviewed but generally unless it clearly states alimony may be awarded in the future, that issue is waived by him.
he has no case, he should have raised that issue in the original case. The ship has sailed.