From Fantasy Shrine:
1-2) Butler Teaches Lesson of Love
"I've saved myself for you because you're my only master for life!"
Sera was acting out his rebellion against his parents, when Makieda, a former butler, came into the picture as a substitute teacher.
Under Makieda's guidance, Sera learned more than just becoming a gentleman. He also fell in love with this butler-turned-…
Amagi Reno
Related works
A divorced man who seemed to have had a one night stand with his children's kindergarten teacher.
The title roughly translates to "My son's been taken care of"
From Shinmakoku Scanlations:
When Tanami Riku's father died in a traffic accident, he was left all alone. Then suddenly a guy named Onikubo Nagi came and demanded to be his guardian in place of his father, who was actually Nagi's former teacher. Then he applied as Riku's homeroom teacher! He pushed himself into Riku's life without even asking for permission. Living with the…