I originally posted a shorter version of this on my writing blog, but I thought I'd cross post it here where there's more readers because I kind of want people's reaction to it. That is, I want people who may have more experience with this stuff to tell me where I'm wrong and where I'm right.
I've been thinking about manga and anime recently. Sex is usually handled so weirdly. It's like, people either seem to have no sexuality at all unless they're creepy perves (Bleach, Kurosagi Corpse Delivery Service, Cowboy Bebop) despite everyone being highly sexualized in appearance, the sexuality is buried underneath constantly thwarted romantic lines to bubble up suppressed (Maison Ikkoku), the sexuality is amped up beyond reason but the "good" protagonists still feel kind of ashamed and embarrassed about it (Demon King Daimao, FLCL), or it's flat out porn (Hentai) where everyone just wants to have sex all the time (but often still feel ashamed and embarrassed about it, though the treatment of sexuality in Hentai porn could be a whole study in itself, which I'm sure someone must have done). Granted, these are all "light" anime (except for the porn) aimed at teenagers, but even more adult works like 20th Century Boys don't seem to portray healthy sexual relationships between consenting adults (or teens), at least between those who haven't been married for a while already. To be fair, I haven't made a study of it, and this is all anecdotal evidence based on the manga and anime I've been exposed to, but it says something weird to me about Japanese culture.
It also makes me think of the Murakami books I've read where people don't really date. It's like there's only three kinds of relationships in Japanese culture, you're either a one-night stand in a love hotel and it's pure sex, you're in some horribly complicated and constantly thwarted romantic relationship that's never actually acknowledged or consummated, or you're married and have been married for some time. Which is really strange.
Compare, for example, these various anime/manga and the American anime-influenced Avatar: The Last Airbender (the TV series, not the execrable movie which will never be spoken of again). In that show we have a number of stable relationships, chiefly between Sokka and Suki and between Zuko and Mai (broken up only because Zuko has to go off and help the Airbender, and then rekindled at the end), and there's also the ongoing flirtation/will-they-won't-they between Aang and Katara which is never portrayed as shameful, embarrassing and never has the kind of exploitative titillation you see in Anime-- Aang never catches Katara in the shower or leers over her body in a swimsuit, for example.
If there are anime or manga that portray ongoing relationships in this way, I haven't seen them. Though I admit it's entirely possible that I just haven't found the right ones.