What's the purpose of romantic relationships?

NPCs are being politely asked to refrain from commenting, "Who hurt you?"

I understand how it's almost a necessity for others but what purpose does it serve for a group with so much physical self-control and psychological clarity?

This is my conclusion but I'm willing to change it. Unless you want to bring another life into the earth, romantic relationships can help in the health aspect.

Anything else is purely speculation.