Amnesia in Female Characters

Here's something I've recently noticed. Why is it that amnesia/memory loss is often considered the "best thing" for women who have experienced difficulty? And oddly, it's often the strong, heroic women who "need" to forget. Here are some examples of this occurrence.

The leader of Cat's Eye (manga). I don't remember the specifics, but from what I remember, the strong leader of the Cat's Eye sisters literally forgets about her thieving career, and another sister remarks that it's probably for the best.
Lufia in Lufia (SNES game). As I recall, Lufia (one of the main characters) loses her memory of who she is and what she's done, and winds up as a normal girl in a normal town, where the hero re-meets her and they fall in love again.
Elmira in Wild ARMS (Playstation game). One of our heroes specifically asks that his once-love and once-great-swordswoman Elmira lose her memory of who she was and what happened to her (she was taken over by a demon and killed many people, etc.). He wishes to spare her the pain of the memory. Elmira, at the end of the game, is no longer a swordswoman, but is now a barmaid. It is obviously assumed she is happier this way. There are some big parallels with Lufia.
Mikami, briefly, in Ghost Sweeper Mikami (manga). Strong-willed Mikami, rather than remember an episode in which she sees she might marry Yokoshima in the future, induces amnesia of the event in herself. Interestingly, she also forces Yokoshima to forget the incident, too.
Cornelia, in Chojin Locke (manga/movie). As punishment for her role in aiding a cult, the strong female character of Cornelia is subjected to a memory "readjustment." She forgets her past and also the affection between her and Locke. In the movie, the once-warrior is seen using feminine lipstick after her "transformation" into "normality." While the act of cutting short the relationship between Locke and Cornelia is clearly ambiguous in its effects, neither character seems to have philosophical or moral objections with the readjustment.
In the gag comic Ike!! Nankoku Ice Hockey Bu, our hero leaves the Earth and causes amnesia in all his friends, of whom the most notable is his (yes, indeed, strong-willed) girlfriend. This example, however, is a little unusual because of the humor-oriented nature of the comic series.
In Tuxedo Gin, heroine Minako suffers amnesia of her penguin friend Gin's death, and her friends let her go on in the delusion that he has gone off with his penguin friends (luckily Gin returns to her in full human form).

The only U.S. equivalent that comes to mind, oddly enough, is the I Dream of Jeannie TV-movie in which (if I remember correctly) the man loses his memory, and the family must start over again....

Perhaps one cultural clue lies outside of Japan, in China. There is apparently a myth of a woman who excelled in the military and who fought amazingly well, but then returned to her home to obediently serve her husband when she had accomplished what she needed to do. There may be some remnant of that "domestic bliss is best for a woman" attitude around here somewhere....