This seems to be a very common problem.
Do you have a photocopy of the divorce decree? Or of the recording ("pronunciamiento") of the divorce at the Civil Registry? Or of the publication of the divorce in a newspaper? If you have any of the above, it should not be difficult to obtain a certified copy from the appropriate Court. On the other hand, to search for a divorce decree in the Dominican Republic without one of the documents mentioned above or without knowledge of the exact date date, place and jurisdiction is not an easy proposition. The problem is that there are no central records and you have more than a 100 local "oficial?as" or civil registries in the Dominican Republic where divorces are recorded, depending on the court that issued the decree.