Option 1:
People live in two seperate societies, one based on the Sun & one based on the Moon.
(Crush) lives in one & (Y/N) lives in the other (You can pick who lives in which one.Option 2:
(Crush) is the god/goddess of the (Sun or moon you pick) while (Y/N) is the god/Goddess of (the sun or moon depends on which one you dont pick for crush)