I can't believe that she'll ever ever go
Knowing she hurts me, obsessionately so

The story:

I finally heard the original version of the song (Devil in HIS Heart,
by the Donays), and had a private revelation. No real
embarrassment here, but I do like relating my misinterpretation
to other Beatles fans. The real lyric seems a bit trite, especially
having become used to the somewhat kinky notion that vocalist
George thinks his girl's obsession with hurting him is a sure sign
of everlasting devotion. I think my interpretation is better in the
sense that it's more amusing, but it really doesn't fit the later
lyric that clearly states: "She'll never hurt me."