Comment: One doesn't need to be thinking about fertility.  One needs to be open to the full fruit of their marital intimacy. 

"Would it not be true to say that when two lovers enjoy one another physically and affectively, it's something that functions on its own terms?"

No, it would not be true.   The purpose of marital intimacy is union/communion a couple, with the full will and love of God.

There are 3, not two.  

Anything short of totality of union (including all of one's faculties) is distorting the love God wants to exchange in marital intimacy.

Drunk sex is actually a significant diminishing of the act, perhaps diminished will, impaired intellect or even impaired sexual response.

Marital intimacy is far bigger than you're thinking of it. 

"physically and affectively" is so far short of the mark.