Patti Boyd's biography is a very good read. Basically it appears their marriage was destroyed by drugs and adultery! George had a wandering eye, even bringing girls back home when Patti was there!! I doubt if George had not been a Beatle and fabulously rich etc., Patti would have stayed in the marriage so long!!
She soundsextremely sad and deeply regrets the divorce from George, now she is in her late sixties. She seems to think that she and George were Soul mates, completely ignoring his marriage to Olivia!!! I
Seems like George at one point was carrying on an affair with Maureen while Pattie was downstairs in Crackerjack Palace.