"I suspect that in another 10-15 more years most of those marriages will have failed. And it will be the women who will become disinterested."
No, this is just their cultural norm. You are thinking in western ways, but you can't compare easily. You are thinking married men and women in Japan grow apart over time, but I think the opposite is true. Many Japanese women still want someone older and financially established who will take care of them and their children and it has worked that way for a very long time when Japan was isolated. Some things have held over in the last 2 or 3 generations after WWII, but culture there is now changing rapidly so that couple's ages are more similar and more women have careers outside the home. This new way puts much pressure on young Japanese males to be successful early, so they avoid dating and marriage to avoid the pressure. It is a bit convoluted and hard for us to understand, and even the Japanese have a hard time understanding. Heck, I have a hard time understanding in our culture how young people can simply "hook up" and still be just friends without it being complicated with a relationship. Dating seems to be a dying art.
Article: "Beatlemania and all the other fads that have followed in the decades since the Fab Four have got nothing on the passion Japan's middle-aged and elderly women have displayed in being the leading force behind the worshiping of Korean actor Bae Young Jun. Squeals of delight, fainting, swoons and crying from hysterical fans were the norm when Yong-sama, or Lord Young, breezed through Japan on tour last week -- all perfectly normal behavior among teenage fans, but the vast majority of the thousands of besotted women were closer to their pensions than puberty. "Yong-sama is the rare type who seems to symbolize so much about pure love for middle-aged and elderly Japanese women," psychologist Takashi Tomita tells Shukan Bunshun (12/9), adding that pure love usually has appeal for two types of women -- those who've never been in love before and others who feel they'll never fall in love again. "The Yong-sama phenomenon clearly falls into the second category. They're involved in settled relationships that have gone on for a long time, but their husbands don't treat them like women anymore. They have little realistic chance of love now or any time in the future. They have these beautified images of past love conjured up from their memories and this fills them with a satisfaction and superiority that allows them to escape from their mundane reality. With ever-smiling Yong-sama always appearing soft, kind and gentlemanly, he's exactly what these women are imagining pure love to be." Non-fiction writer Yuki Ishikawa, who frequently pens pieces about Japan's housewives, says that middle-aged women's lusting after Young comes from the same source that makes them so formidable while shopping or trying to snare a seat in a packed train carriage. "Most Japanese housewives have been married for a long time and gone through a lot of disappointment and betrayal at the hands of men. Yong-sama is the polar opposite of the men who have put them through this as he gives them hope and the belief that he would make their life pleasurable, which is what inspires even generally inactive biddies to act like groupies," Ishikawa tells Shukan Bunshun. "What's happening now is not far away from earlier reactions to (foreign) people like (actor Leonardo) DiCaprio or (soccer player David) Beckham. And because the women have no guarantee of ever feeling for somebody more deeply than they do Yong-sama, they go after him with even more verve than they show when swarming department stores at bargain sale time because they think, 'If I don't grab this chance now, I'll never get another shot at it again.'" Shrink Tomita notes that other acts, like the all-girl Takurazuka dance troupe and heartthrob enka singer Kiyoshi Hikawa, also attract older women groupies, but there's a difference when it comes to chasing after Young. "They are acting as women and there's not a hint of maternal instinct behind their actions," he tells Shukan Bunshun. "If these Japanese women are so caught up in an imaginary world, it's proof of just how they're incapable of dealing with their reality. If their relations with the opposite sex aren't particularly good, they're bound to chase after an ideal that appears before their eyes. It's the same mechanism that triggers the fascination male geeks have for little girls. I think it's fair to say that the sheer number of women chasing around after Yong-sama and the deep passion they show for him is a barometer of how little men have been treating their wives as women." "