Although divorce has increased a lot in Japan in percentage terms, it is still far behind the US or UK, and a lot of those divorces are among older people.
I don’t think anyone believes the Japanese are more happily married than Westerners, but I have heard arguments that suggest that the lower divorce rate is because of more realistic ideas of what marriage is for or even a selling point for the stability of the semi-arranged marriages that are still surprisingly common. As often is the case, however, pressure from society is almost certainly more of a factor:
“Women tolerated bad marriage because the alternative was intolerable. Even in postwar Japan, divorce left women virtually unprotected and cast a lifelong stigma on the children, cutting them off from a good job or marriage.
… A 1993 poll of Japanese found that less than half of those interviewed said they would marry the same person if given the chance to do it over again… The most commonly cited benefit of marriage was not love or companionship but acceptance in public as full-fledged members of society.” About Face pg 57
Once they are retired, the Japanese no longer have to worry about social pressure or the effect on their already married and employed kids. The other factors for divorce among the retiring baby boomers include:
– Wives having seen very little of their husbands while they were working, and so reacting negatively to having them around the house, being expected to spend time with them, or just to finding out who they have really been living with all this time
– The husband becoming even more useless and offensive due to unhappiness with being retired, e.g. because they have no idea how to spend their time without work and work-related socializing to fill it in
– Negatives that were seen as a side effect of typical Japanese working life and its accompanying long hours and stress like drunkenness, abusiveness and not helping around the house remaining true or getting worse once they retire
– Retired husbands often spend more time back at the family home, either due to wanting to get out of the city or to look after even more elderly parents, and the wives don’t want to accompany them
“Even after death, husbands aren’t getting the respect that they used to: A growing number of women are resorting to shigo rikon – ‘divorce after death.’ Wives refuse to have their remains interred with their husband7s in the family grave.” About Face pg 64