I do want to remind you that what you want are, in fact, fantasies. Nothing will ever be perfect and I feel it is healthy to be content with the way the world works. I don't say this to dissuade you from being happier. It very well may be that finding someone else could be the right choice. But just keep your head level a bit.

I feel that your being less interested will pay a toll on him. And I'm not sure that it's fair to continue with a relationship when you spend most of your time day dreaming about something else.

While darkfae's story is encouraging towards the BDSM side, I don't know that those results are typical. Frankly, if the guy was begging her to come back, then I feel maybe anyone would have been better (I don't mean this in offense, just to show emphasis that he wasn't the most.. domineering person). Keep a few things in mind about a BDSM life ahead of time. Are you planning on having a demanding job? Do you want to get married? What about children? Family? Weigh the contrasts between your vanilla world you imagine yourself in, and the BDSM one before making any big decision.