My favorite part, especially as of late, is the sense of exploration and growth my wife and I share, and the effects that has on our life, both in and out of the bedroom.
We're a couple that is wiling to try most anything (twice), and lately we've been trying a lot. Stepping outside of our comfort zone. Pushing ourselves to be more open. Willing to risk a little bit of discomfort for the immense pleasure of learning something we never knew about ourselves or each other. (For the record, we've been fortunate and have taken things slowly, so we haven't had a lot of discomfort to deal with, but it is inevitable).
That sense of being open-minded, trying new things, listening to your mind and body, obeying what it tells you is right and wrong, good and bad, then learning and growing because of it, is something that every person and every couple should experience. The effects it's had on our lives outside the bedroom has been profound as well.
I feel very lucky and grateful that sex (nay, GREAT sex) can do that for us, and that's what I love most about it.