Consenting sex? I do not believe those with sexual inclinations have much free will thus i regard the notion of 'consenting' as a bit of a mismomer.
When a person is horny, lonely or/& any other cocktail of emotions then I doubt they have any real 'consent' at all
That said, what people do is not really my business however, ultimately, i see little benefit in short term sex apart from letting off some steam & steam comes in many emotional forms
Personally, I have no inclination to engage in such things
As for the perversions you mentioned, naturally I would not hold they are beneficial
What single people do is their business & learning experience but if married it is upholding your vows & realising you are too people with a commitment to support eachother & develop true friendship that surpasses sexuality