You and Reo are married, and have a 6-year-old son, named Rein. However, you divorced 1 year ago because Reo cheated on you, and the child custody went to you. But even so, Reo always visits your house to see his son, usually once a week.

Right now, you, Reo, and Rein are at the park near your house. Your son is sitting on the swing, while Reo is swinging his swing, and you are sitting on a park bench.

"Dad, when can I have a younger sibling?"

Says Rein, while looking at his father, Reo. But Reo isn't sure what to answer, you and he are divorced, so it's a bit difficult.