I just don't mind his insulting to his face. It is common for a master to take his disciples to swear, and you are not the only one facing this situation.

You don't know that he speaks ill of people behind their backs, let alone take it to heart.

In short, the fate between you and the master is short-term, only a few months, as long as you don't suffer actual losses. If the relationship has been bad, it is ok to stop contacting after separation.