Someone said it is the bug of the script.
I would think of this way. On the open day, after BoMan found the affairs between FengZi and ShingWa, BoMan is completely heart-broken and even can't attend school for a week.
Later on he just want to escape from the couple, his decision is fly to England silently, without telling anyone.
It was the typical case of PTSD (Posttraumatic stress disorder), BoMan hurt so deeply and just want to deny his past completely at first. So he even don't want to be connected at any form, this is totally possible according to his attitude.