D/s: Questions

24 hours ago, I was spread-eagled, face down on the bed, wrapped in rope and being throughly spanked. I've had a day to think everything that happened over and have some thoughts and questions:

As I get further into this exploration of my sexuality and submission, D/s, what will happen to the more vanilla side of my sex life?
I suspect that I'll begin to crave D/s as an active part of any future relationships--it seems so addictive, compelling, and expressive to me--but is that true/typical?

When J laughs and says "I want to hurt you, but not in that way," he's explaining why he decided not to do a specific thing with me, and hinting at experiences to come.
What makes a Dom want to hurt a sub, assuming he/she is not a sadist per se? Is it the power and control and the posession that inflicting and receiving pain demonstrate?

I LOVE what we are doing, and it bothers me that I can't talk about it with family and friends. Everyone I know would be SHOCKED that I am having such a wonderful time being tied up, spanked, face fucked, used, etc...but by someone with whom I am building such a caring relationship. Discovering how intensely I feel is one of the major revelations of my recent adult life, but it's something I can't talk about--except with J, who is a great listener and has lots of thoughts of his own to share.
How do you handle this part of your life with others? Is it walled off? And if you talk about it, how do you describe it?

A memory from last night:
Me, fishnet bodystocking, heels, clamps, rope, lying on the bed after J used my mouth and I got so excited I almost came. He said "I want you to think about yourself here, naked, clamped, bound with rope. Are you my submissive slut?"
Yes, I said, Yes, and my pussy tingled because what I want the most is for this man to use me and for me to please him.

And just think, 6 weeks ago, I didn't know--and hadn't experienced--any of this.