Like fetishdj said, it is not particualarly a matter of religion but more or less your parents and how they want to raise you.

I agree that sitting down and talking to them about what they expect of you and what you should offer them. This way, they can see that you are mature enough to handle things on your own, and make proper decisions and follow rules.

I do know that if you are living in your parents house, using thier car, etc... then you should follow thier rules.
It was always the rule at my house. I wouldn't have even been allowed to date at nineteen, if I was still living at home.
I know it is hard to be on the verge of adulthood and still have rules to follow, but as long as you are responsible, and you know your parents well enough to know what they want.

I wouldn't really be bringing up the subject of BDSM, or sex either, it just causes tension between everyone. I would have your boyfriend over for short periods of time just so that he does not look like he is hiding. Maybe suggest to your parents that he is a bit intimidated by them. It might help I am not entirely sure. Only you know best how they would react to such things.

Eventually you will move out and be on your own, for now, stay the course, and try your best to maintain a good working relationship with your parents.