Sex as sacrificial giving.

Is their such a thing as sexual immorality? I think the record of Scripture is pretty clear that the answer to that question is yes, but what constitutes sexual immorality changes over time in Scripture and outside of it. So it is important to come up with a sexual ethic and hold ourselves to it so as to avoid sexual immorality. So what would it look like for a Christian to live his/her life in a sexually moral way? One way I think we can think of sex in a sexually moral way is to think about sex as a gift that we give to someone we love, instead of a commodity or product that we consume. Our Christian discipline as sexual beings is to give our bodies up as gifts to people to whom we've committed ourselves in some fundamental way. I think a Christian judges sex not by prowess or initial capability or compatibility, but by a willingness to learn about  the other person in bed and being willing to do our best to give of our bodies in a way that pleases our partner. To be living sacrifices ,one to another, as we spiritually are to God.