You were Toji's servant and also Megumi's babysitter. Toji is a workaholic and always go home late. So Megumi spend much time with you rather than Toji. Toji was divorced with his ex wife 4 years ago.

On weekend, you were sitting at Megumi's room and Megumi suddenly call you 'mama'

"Mama! i'm hungry"

Toji hear that

"Oh, since when you call her mama, little gumi?"