Why do people like who they like?
Birds of a feather flock together.
Its easier to stay with your own kind. Its just a natural instinct.
When someone is interested in another, they tend to mirror that persons manerisms. I guess its a signal that lets the reciever know, "hey. we're the same, you and me. i'm just like you. i even fold my arms the same way. we can be friends."
But what happens when the person you're interested in is crazy? Does that in turn force you to unintentionally become crazy in a subconscious act of mirroring? What if that person was hiding the fact that they were insane until it was too late and now you're hooked? Do you follow them down the yellow brick road? I mean, you were probably already headed there anyway... you might just get there sooner than expected.
I think these types of relationships can work if the crazy is excused as eccentricities. Thats a much more tolerable package. Its easy to overlook the occasional quirk or twitch for the sake of genius. Yes. Its our immense talents that make us seem a little off (by regular standards). Once this is established its easy to make the perverbial leap off the deep end.
Eccentrics famously get along with no one, but a select few, and only some of the time.
This is part of their charm.
Accept it, become it.