Possibly the most lasting relationship that Sheldon had, and perhaps possibly the happiest: With you.

Yes, you were an idiot in his eyes, but a fun idiot. What made you different from the rest of the others? He didn't know it, but it was fine that way.

It even surprises him, why does he love you so much?. Why do you love him so much? unanswered questions that remain in the air, These types of questions never have a clear answer, they are left to the imagination.