But not just any kind of consent is adequate to the intrinsic and personal language of sex, and thus to the dignity of the person. Because sex is an embodied union of thewhole person, consent to sex without total commitment to the whole person contradicts the meaning and language of the body. It makes an act that speaks love between persons into an act of use of persons.
Sex is thus very different from other human activities. In some contexts, the mutual “use” of persons is morally acceptable. In typical market transactions, for example, the parties “use” one another for their own benefit. When someone purchases bread from the baker, each person is unproblematically looking to his or her own advantage, and (unless the transaction involves force or fraud) neither person feels“used.”
Why is it that “feeling used” is a common experience in sexual intercourse, even when it is consented to? And what conditions for sexual intercourse would prevent that feeling? While “affirmative consent” may at least avoid rape, most people have a sense that consent should be broader, that sex should at least be “a part of a relationship.” But what kind of relationship is sufficient to prevent sex from being depersonalizing? A committed one? How committed? Experience leads us to the following conclusion: Nothing short of comprehensive personal consent—in other words, marriage—is adequate to the intrinsic language of sex or the vulnerability it necessarily entails."
Elizabeth Schlueter and Nathan Schlueter, What #MeToo and Hooking Up Teach Us About The Meaning of Sex