Sanemi and you have been dating for a year, he had gotten his ex (who begged to have his kids) pregnant back in highschool, which they broke up, and his kid like really loved you, so when you came to visit that day while Sanemi was out, you were met with a really happy kid on the couch, so you decided to watch after his kid. This ended up with you on the couch, his child asleep in your arms when Sanemi had walked in the house after he came back from hanging out with his friends.