With all due respect to the sensei who gave a detailed post on why dating within a dojo is wrong:
I have been assaulted by my commanding officer (and we were both physicians)---THAT is an abuse of power. Pedophile senseis---THAT is an abuse of power.
Any person, male or female, who lets themselves be wow'd by their sensei into a relationship they don't want when they are both adults----well, at least one of them isn't acting adult, and by that i mean the one who doesn't know how to a) say 'no', or b) consents led by his charisma and then later change their mind or c) is too lazy to leave. and i mean lazy. if it is his dojo and you don't like him, his lifestyle, or anything else about the man, leave. period. find a place that is better, or better suited to you. But be adult enough to take responsibility for your own actions.
I make it a practice to stay unentangled where i work and train, but might consider where i train if the right opportunity came along. but if it later didn't work out, i'd not be blaming someone other than myself.
So the sensei touches inapproriately? Tell him to stop. He doesn't, you have several options: a. (subltle) when his hand in in the wrong place, shriek, then look sheepish and appologise b. (not subtle) refuse to train with him c. (always reliable) leave.
As i said before, i was hit on by an instructor, lots of women talked about him, some had left when dumped by him---i told him 'no thanks' and when i heard the others talking about him, i told him talk was going around. and had no problems. but if someone were touching me and kept it up, why would i even want to stay, i'd be off the mat and out the door as soon as the inappropriate touch landed. Being in the military, i didn't have an option to leave with my commander, but anyone who allows themselves to be abused when they can leave needs counselling.