She's a Man in Japan is basically "Gender Flip via Localization," where Executive Meddling results in a character's sex being changed to meet the perceived needs of another market.
The damage is done, there’s nothing you can do so don’t torture yourself over it. Most men would rather walk over a bed of burning hot coals than tell a girl to her face they’re not into her. And most of the time, they will reason that the girl is probably on the same page so there is no need to reach out.
I’ve been there, so believe me I know how awful it feels. Like many women, my reaction was a mix of rage and indignation. Because it’s an uncomfortable conversation to have and he doesn’t want to have it. Also, men just aren’t as equipped to handle emotions and emotional situations as women are, so they avoid them. They tell themselves that she must know this isn’t going to work out and calling and telling her something she already knows would just be silly, so that’s the end of that. If he disappears, it’s because he isn’t the right guy for you.
Sometimes it's the same person, sometimes it's a man and woman sharing one body.
If a man and a woman bodies, it's a variant of "Freaky Friday" Flip.
Man, I Feel Like a Woman, Different for Girls, and Attractive Bent-Gender are also common enough that they approach the level of Law.
Contrast with Rule 63 and Gender Flip, two tropes generally related to "alternate" versions of characters who, In-Universe, have had the "opposite" gender from what the audience would expect.
I’d arch my back, refuse to do positions that made me “feel fat,” and drape different parts of my body with a blanket or pillow to hide my increasingly chubby body.
Sometimes that made me feel more at ease, but mostly it became tedious, distracted me from feeling sexy, and annoyed the crap out of my partner who just wanted to see his hot girlfriend naked.
Maybe his vanishing act came after a period of him pulling away. It doesn’t matter, it means the same thing: he’s not into you and doesn’t see this relationship going anywhere.
Maybe he met someone else or maybe he just had an epiphany.
Dating was evil and Courtship, whatever it was, was godly, good and Biblical.