Ore Wo Dame Ni Suru Yuki-Chan Sensei summary:

A man who has nothing to live for goes looking for Yuki, a girl he met five years ago. Yuki is now living in a nursery school, taking care of the children as their "Sensei". When the man is reunited with Yuki, she treats him as a "dear friend," and suggests that he can stay with her. Yuki offers him motherly love and genuine acceptance, so he stays at the day-care center hoping to "keep Yuki to himself" - but what happens?A depressed man now has a sweet and fluffy girl all over him in this obsessive doting love comedy!(Source: Comic Gamma Plus, translated)