Seriously, it would have to be Karnilla. She checks all of the boxes:
1. Beautiful beyond compare (yes, I'm a sucker for amethyst eyes) and if she wanted to, she can alter her appearance to suit her whim ... or for role playing purposes.
2. She's a goddess of royal standing, projecting eternal youth, the wisdom of the ages, and vast wealth. Every man is a king in his own castle, but I would literally be a king in a castle.
3. Her magical abilities are unmatched save by perhaps Loki and Odin. I imagine in this scenario that I'm an otherwise normal, non-superhuman chap, so I'd definitely study magic under her. And if that didn't work out, well, she's also powerful enough to bestow superhuman abilities on me that last permanently, or whip up some enchanted talisman or other that gives me powers. No point in existing in a superhero universe if you're a complete flatscan with no powers or abilities.
4. She loves deeply, honors loyalty, is brilliant and cunning and if provoked, absolutely ruthless. I'd never ever worry about someone threatening her -- or our children -- whenever I'm away. I suppose if she's the jealous type I'd have to keep all of my platonic women friends at a distance, but hey, that's no different than now. (Just kidding, honey. Sort of.)
5. She's Queen of the Norns and knows your fate intimately. When she says that the two of you are meant to be, you can believe her without hesitation. When you know, you know.