This week, we've been studying I Corinthians 7, which has a lot of instructions about sexuality, marriage, divorce, and some about slavery. He included a quote from Martin Luther that I found rather fascinating. Sexuality in our culture is way overemphasized in some regards, but is under emphasized in others. It carries with it a bit of taboo, and it is often portrayed as a puerile sort of thing. Guys are portrayed as thinking about nothing besides sex, and it's fairly expected that people will do little to restrain their passions. Hence, in condemning the bad behavior it is easy for Christians to take it a step further and condemn sexuality itself.
I knew of a preacher near Rose Bud who actually got fired several years ago because he used the word "sex" in the pulpit! Paul places a high level of importance on married couples being united in this way, and he even seems to present one's libido as a perfectly viable reason for choosing to marry (though that is certainly not the central point of marriage). You won't find anything in Paul's writing that suggests one having sexual desires is to be equated with spiritual immaturity.
Even if you don't agree with Luther's conclusions--I personally don't, I think he understood how seriously Paul viewed the role of sexuality in the life of a Christian:
One spouse may rob and withdraw himself or herself from the other and refuse to grant the conjugal due or to associate with the other. One may find a woman so stubborn and thick-headed that it means nothing to her though her husband fall into unchasteness ten times. Then it is time for the man to say: If you are not willing, another woman is; if the wife is not willing, bring on the maid. But this only after the husband has told his wife once or twice, warned her, and let it be known to other people that her stubborn refusal may be publicly known and rebuked before the congregation. If she still does not want to comply, then dismiss her; let an Esther be given you and allow Vashti to go, as did King Ahasuerus (Esther 2:17).Had you ever thought about bringing up what is happening (or not happening) in the bedroom before the congregation for church discipline? Yikes! It seems that he is viewing sexual deprivation on the same level that most Christians commonly view adultery.
(Quoted from Ewald M. Plass, ed., What Luther Says: A Practical In-Home Anthology for Active Christians (St. Louis: Concordia, 1991), paragraph 2811)