[quote=Agent B52]
Then how come they're together in the first place?

Also, bookface. That amuses me greatly for some reason.
[/quote]

To prove his manliness? Maybe they were set up and neither particularly liked the idea? As far as I know, Hephaestus generally preferred contact with his automations, not the other Gods. Aphrodite was gifted to him for his loyalty but he couldn't exactly 'do the do' and thus, they had no children!