"Does divorce make people happy?"

The simple answer seems to be no. It seems that most unhappy marriages will get better as long as the spouses have a commitment to commitment (and were in a community with a similar view towards commitment)

Many currently happily married spouses have had extended periods of marital unhappiness, often for quite serious reasons, including alcoholism, infidelity, verbal abuse, emotional neglect, depression, illness, and work reversals. Why did these marriages survive where other marriages did not? The marital endurance ethic appears to play a big role. Many spouses said that their marriages got happier, not because they and their partner resolved problems but because they stubbornly outlasted them. With time, they told us, many sources of conflict and distress eased. Spouses in this group also generally had a low opinion of the benefits of divorce, as well as friends and family members who supported the importance of staying married.

It's also interesting how useless much modern marriage counselling seems to be, and the final sentence is almost noteworthy:

Spouses who turned their marriages around seldom reported that counseling played a key role. When husbands behaved badly, value-neutral counseling was not reported by any spouse to be helpful. Instead wives in these marriages appeared to seek outside help from others to pressure the husband to change his behavior. Men displayed a strong preference for religious counselors over secular counselors, in part because they believed these counselors would not encourage divorce.