Can't see it that way. Everyone raised eyebrows at the haste with which Paul remarried after Linda's death. The boy made a very bad call. I think it's a bit too easy to blame stupidity on kharma.
No, I think Paul McCartney could secretly be the world's biggest bastard and he wouldn't have deserved Heather (or her leaked allegations or McFartney cartoons).
I'm suspecting that Paul was maybe one of those high-ranking Nazis scientists or maybe even Attila the Hun. There are hints in the songs: "V-bomb flying in the dead of night . . . ."; "Get back, get back, got a city wanna to ransack . . . .";