Kal and Tom, Unchecking one of the principals will work in most cases, although you could get into an argument about the event not being "principal" for one of the spouses. You would have the same problem with other two principal events, e.g. engagements.
You will still get two occurrences if you do an ancestor FJ report and the divorced couple are "ancestors". In one section, the husband is the prime person but there will be a list of the wife's principal events (which would not now include the divorce). In the next section, the wife is the prime person and you get all the events where the husband is principal (including the divorce, again). This redundancy occurs with all "principal" events for either spouse. (If you had both spouses as "principal" the event would be described four times.) I end up editing out the redundancies in my word processor.