My Wife is Wagatsuma-san

is a manga written by Yuu Kuraishi and illustrated by Keishi Nishikida. It was serialized in Weekly Shonen Magazine from September 20, 2011 to September 24, 2014. It is complete in thirteen volumes. Kodansha Comics has licensed it for digital release in English.

Plot
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?!

Official
Official English site