My Wife is Wagatsuma-san 8

One day, a super-average second-year high school student who wants a girlfriend, Aoshima, suddenly awakens to the ability to time slip. Ten years in the future, he is—gasp—married to the cutest girl in school, Wagatsuma-san! In the present, they are only classmates, so how in the world does he end up with the unobtainable Wagatsuma-san?! A time-slipping romcom coming at you from Yuu Kuraishi, the writer of <em>Fort of Apocalypse</em> and <em>Starving Anonymous</em>!