@Khoopa—
I wonder what you see as the
general concept of romantic betrayal.
Let's say that Hito is a heterosexual male in high school, with interest in Shiboko, that she is consciously aware of his interest and willfully encourages it, and that they talk of their plans to go together to university, but as they day of graduation approaches, she admits that she is not going to go to university with him because she has planned instead to marry Nioirou. Most of us would regard that as romantic betrayal. (And, people being what they are, many in Hito's position would think that of Shiboko even had she never recognized or encouraged his interest.)
The difference in this story is just that a homosexual or bisexual woman was misled.