People treat you how you allow yourself to be treated. If you want his services more than he wants your money, this will work out for you. If you cancel every time he's going to be late because you have other plans, he will either stop being late, or you will stop seeing him. Like you said, you're OK with it, so it works for both of you.
If his communication is good, and he asks if it's OK, that's a different story, but if he was just late without communication, I'd just treat that as cancelation.