Changes of Heart, Volume 7 (Changes of Heart #24-27)

Koyori and Hijiri are two people who grew up together as friends, and are now a couple, living together. But when both of their exes marries the other, the two begin contemplating their own "marriage." But one time, in the midst of passion, Hijiri blurts out "Will you marry me??!" Is this it? Can it be? A proposal?!