Take him out of this equation for a minute and ask yourself "What is best for me?".
Seems to me that wanting some serenity in your life is a goal here, and any contact with him, at this point, is ruining that serenity. Talking once a week *may* help, but to be quite honest, I don't know what you're getting out of any contact with him at the moment.
And yeah, I think you're doing real awesome by sticking to your boundary. It's totally ok to have "gotten it" by the second try; heck these aren't SAT exams...it's a personal boundary.