Spiders don’t have to eat their mate. The female just tends to be hungry, after mating. The male is snack sized, right there, and of no further use.

Apparently, when trying to breen endangered spiders, they make sure the female is well fed prior. It gives the male a chance to make a quiet getaway.

*eats him out

Spider: Nice.

*proceeds to sex

Spider: No! You’re doing it backwards!

Some spiders do hang out to watch courtship. Male wolf spiders (called eavesdroppers) will watch and mimic other males performing taps and whatnot.