This one is unpopular with the young (i.e. typical Reddit users), though it gets increasingly popular with age...

For our species, emotional connection, in a sense, is the entire point of sex. Emotional connection fosters deep bonding between/among sex partners, so comparably helpless human infants, born long before our large brains are much developed, allowing our heads to fit through our birth canals, can get nurtured by at least two committed adults, respectively. For better or worse, emotional connection is what human sex has been leveraged for, by forces of evolution; it ultimately supports our vast brainpower advantage over other species on Earth. Human sex incorporates so many things, unlike sex for other species—from our characteristic endocrine responses, to the precise locations of our genitals, to the female orgasm phenomenon—to reinforce emotional connection.