Sweet vs. Home

Living with a whimsical mother is hard enough for Tatsuya, but he is soon faced with an even bigger challenge; he finds out that his mother has married his teacher, and right after marrying suddenly disappeared. Kind hearted Takaoka, her husband, now has the burden of taking care of Tatsuya. They live together, and get along fine, but as their bond tightens Tatsuya soon starts having an ulterior motive...

Hatsukoi (初恋, First Love)
Koizumi's first love rejects his confession on the last day of elementary school. Forced to move to another town, years later Koizumi returns. At the start of high school, Koizumi and his first love are reunited.

(Source: Tousuisha, translated)