If she was your first love then why did you marry some random dude instead? Contrived.
Following cultural traditions is deeply ingrained in Japanese society. Because of this, it wasn't uncommon for a lesbian to marry a man to satisfy her family’s expectations and aim for "normalcy" in the eyes of society. As she secretly visit brothels and lesbian bars.
Of course, this has been changing rapidly in modern times, especially in the last decade, with an increase in LGBT presence in Japan and more support among the youth.