As for communication. If I were your RP partner, I'd prefer honesty. You don't even have to mention the reason, as long as you're up front. I'd be way more displeased with learning someone tried to pull some fade away shit, rather than telling me straight up they're not feeling the RP anymore. I may not be representative for the 1x1 community, but fuck, that's common decency. If you don't want to discuss your reasons, tell them you're uncomfortable with the subject. If people continue to harass you, ask them to stop. If people don't stop, report them, then block them.
Just make sure you take the high road. It might be a little harder, but at least you'll be honest. You don't solve conflict by running away, especially not if that conflict is with yourself.