Oh how Spike would fancy himself as Rhett Butler... Oh how @WhiteAvenger would fancy Spike as Rhett Butler... 😛
Only to the point that, frankly, my dear... well, you know the rest of the quote.
I like Spike with Buffy best because I SAW Spike and Buffy first, which will always make Buffy Spike's girl for me. That's the exact same reason that quite a few Bangels see her as Angel's girl, if they'll just admit it. Frankly, both relationships suck (vampires, you know) but Buffy and Angel just has too much crying and, "Oh, if we only could, but we can't..." and "Maybe someday but I just don't see how..." and let's not forget "It's too dangerous for both of us, so I'll run away to the big city, but I'll keep tempting fate by coming back..." in it for my taste. At least Spike and Buffy get down to business, whether fighting or in bed. Passion, I can accept, even the less than healthy kind just as long as both parties KNOW that that's what it is and can get a little mutual, albeit momentary, pleasure from it. By Season 6, Buffy is an adult, not some dreamy teenager with delusions of Harlequin Romance love affairs, and even as troubled as she is, she doesn't have any delusions about what she was getting into. "This isn't real, but I just want to feel..."
What Spike and Buffy had in Season 6, bad as it was, at least provided Buffy with an outlet for her anger and frustration, and it also has to be remembered that, without that relationship, violent and destructive as it was, there would have been no incentive for Spike earning his soul and becoming the Champion that he was fated to be. So, even if it was bad, the ultimate results, realized in Season 7, was good.
So, yeah, at second thought, maybe I do see Spike as Rhett Butler to Buffy's Scarlett O'Hara, but only because Angel makes such a GREAT Ashley Wilkes. The way that I recall that story, Scarlett finally realized that she and Ashley just weren't meant to be, and when she finally admitted that she loved Rhett, he said, "No, you don't, thanks for saying it, but frankly, Buffy, I just don't give a damn."
(And before anyone decides to jump all over me, it should be noted that I'm currently pumped full of pain medication due to a dislodged kidney stone, so frankly...)
And it's all Miss K's fault for bringing up "Gone With The Wind."