Isn't it good to be able to leave a bad marriage rather than grimly suffer through until one or the other spouse dies? I really don't see that longevity in itself is a great goal.

Not the highest
The top five highest divorce/separation rates by occupation were the following:

“Dancers and choreographers” at 43.05%,
“Bartenders” at 38.43%,
“Massage therapists” at 38.22%,
“Gaming cage workers” at 34.66%, and
“Extruding and forming machine setters, operators, and tenders, synthetic and glass fibers” at 32.74%.

-but high according to this:
"There was not a specific occupation listed as Marriage and Family Therapist in the same study, however, there were multiple occupations in which a Marriage and Family Therapist may fall. McCoy and Aamodt listed the occupation “Therapists, all other” as having a divorce/separation rate of 24.20%, “Sociologists” as 23.53%, “Social workers” as 23.16%, “Counselors” as 22.49%, “Miscellaneous social scientists and workers” as 19.65%, and “Psychologists” as 19.30%. Each one of these categories had a divorce/separation rate well above the national average for all occupations of 16.96%."
Do Marriage & Family Therapists Have Better Marriages? – The Family Therapy Blog