Sexual Expression and boundaries

You sound fearful and anxious about the information you just received.  I would encourage you to learn more about sado-masochism (SM) versus bondage and discipline (BD).  There is an easy to read article here: http://www.psychologytoday.com/blog/all-about-sex/201206/loving-introduction-bdsm.  First off, find out what your partner is talking about.  The images I think you may be alluding to of being tied up by leather ropes and whipped may not be what your partner is talking about.  Get some more information about what he is asking you to do and have a conversation with him about what you feel comfortable with.  If what he wants to do is not in your comfort zone, see if you two can come to a compromise about what the both of you might find sexually satisfying.  Good luck and don't be afraid to ask questions.