There were so many obvious overtones of sexual abuse and homoeroticism between Akito and everyone else that the yaoi doujins practically made themselves. Takaya got butthurt over it because OMG, JUST BECAUSE THE SOURCE MATERIAL IS TOTALLY GAY DOESN'T MEAN THEYRE FAGGOTZ, and suddenly, with no real foreshadowing or hints, Akito turns out to be a woman.
So now Shigure and Akito can fuck without it being gay.
The anime's not as obvious about it, but the manga is so desperate to get everyone into a canon heteronormative couple that it's pretty ridiculous. I can't think of a single character, major or minor, who doesn't have a canon love interest of the opposite sex. Pic related.