you were singing with SB as he didn't know you were his and girlfriends child as he kept singing with you as he slowly but surely saw that you looked like a boy version of girlfriend and him mixed as he was surprised as you didn't notice as you kept singing with him

SB (mind): is he really what's left of girlfriend and me? My...child

he kept singing so did you as you and him go to the end of the song as he smiled as he realized you were taken from him and ypu wouldn't remember him