Re: How to Say No
While the thought of saying no via Nikyo is entertaining, it would only invite him to ask her out by precisely the same means a minute later, at which point the entertainment value does a 180°.
I also think you should involve your husband. You don't have to set the stage for a no-holds-barred match, but assuming we're all adults (excluding your pariah-paramour, oh, and your dojo), he should be given the opportunity to support you.
Ditch the Dojo, this is harassment. Don't feel bad that your psychological resiliency helped to maintain your optimism. If all you're giving us is that the dojo won't intervene, and that he won't quit, then quit.
If this dojo is such hot-stuff, then you've picked up a good bit of training in 6 months or so. Take it, and make up the time lost at the gym. In a year when you've moved on to greener pastures, you'll be in the best shape of your life and recovering anything you may have lost will be a cinch.
Part of my response is fueled slightly by the anonymous nature of these threads, You never want to accuse/blame/punish someone who is honestly in a fix, so please understand my guarded concern for a stranger's well-being.
Even so, if all of this is factual, I think it still applies.
If not, then I don't have to bother with what I think of posts like these.