Sexually addicted to [Yoko Ono], he was helplessly dependant, a predicament grindingly obvious in his chord sequence: the sickening plunge from E7 to Bb7; the augmented A that drags his head up to make him go through it all again; the hammering flat ninth that collapses, spent, on the song's insatiable D minor arpeggio. Nightmarishly tormented, this is a musical tryst with a succubus. No wonder the lyric consists of the same phrase over and over again. Lennon is literally obsessed.
Ian MacDonald gets himself all worked up about the bridge to I Want You (She's So Heavy) in Revolution In The Head (pp. 343-4)