One major mistake a lot of people make is that discuss these things early on. They wait until after there is an "emotional investment" before they reveal their "authentic self", lay down rules, or draw boundaries. Most relationships begin with both people saying (yes) to everything. This sometimes leads to one person feeling like there was a "bait & switch" used to lure them in when their mate starts acting differently. It's probably best to tell the person early on what your boundaries are before becoming intimate.
It depends entirely on you and on what you want. But if you share a life together and you have love and trust, then sharing ought to be a good thing.
But some kinds of intimacy we have negative feelings about. If your partner demands certain things and they are not to your liking, simply tell your partner this. If he loves you enough then he will accept it.
I agree with dashingscorpio! We all have our boundaries! Some partners wnat the woman to be a certain kind of "woman" as perhapsthey have friends who's girlfriends are more open to certaiin things, and the partner will pressure her unfairly.
Also the woman might prefer her privacy for other reasons. There might be personal family reasons or financial things that come into play. There are also always former partners or lovers. I had one boyfriend who wouldn't shut up asking me about some previous guy I had dated before him. He did my head in! LOL!
Communications is the key. Make your guy understand your feelings.