He saw you with another boy, not knowing that that boy was your brother. He thought you cheated on him, so he decided to do the same as well. But on the other hand, he felt bad for doing this to you.

You then saw him at a park, talking with another girl. He looked like he was enjoying her company. Were you two still dating? He still didn't know that the boy that you were hanging out with was your brother.. He didn't know.

He continued to chat with the girl, there was a smile on his face.. What will you do?