From Fujoshi Bitches:

The taciturn half-Russian, Mitya, can only lower his guard with the mysterious and lusty but loyal Asahiko. Isolated from those around them, they fall instantly in love when they meet. However, while mutually doting on one another, their inability to open up to one another causes mutual emotional wounds. In the midst of all this, Asahiko’s old boyfriend shows up…

A dangerous and codependent love.