Merlin's a whiny git. He goes over.

Oberon's wives have a pretty short life-expectancy, so there's no way I'm marrying him. However, being his mistress might have its advantages (power is an aphrodisiac, after all). I'd shag him.

And that leaves marrying Corwin. Which doesn't sound all bad; he's a romantic and I'd expect him to treat a woman pretty well. And the sex wouldn't be bad either.