To try and answer this question, I of course turned to Wikipedia, the repository of all knowledge (and accuracy, right?)
The article on Yoko Ono discusses her relationship with Paul McCartney during and after the breakup and following John's death (see
here). A good deal of the straining of relationship between them stemmed apparently from an agreement that John and Paul had, to credit all Beatles songs, whomever actually wrote them, as "Lennon/McCartney". Paul wanted to switch that around following John's death, and drop John's name from the credits of songs that he wrote alone, but was outvoted by George and Ringo, as well as Yoko.
The article on
the Beatles gives sourced statements that Lennon's relationship with Yoko created creative tension and differences between Lennon and the rest of the band; that John brought Yoko to recording sessions despite a long standing agreement within the band against brining in partners or S.O.s; and that George "disliked" Yoko. John subsequently became "increasingly contemptuous" of McCartney's writing, going so far as to call "Ob-la-di, Ob-la-da" "granny [poop]".
The
Lennon article also cites John's increasing drug use as a factor in his distancing from the others. Creative differences included disagreements on management, producers, and songwriting credit, according to the article. In a cited 1970 Rolling Stone interview, John referred to what he perceived as "hostility" towards Yoko from Paul, George and Ringo.
The George Harrison article makes no mention of any animosity he might have or have not felt towards Yoko. The Ringo article makes no overt mention of his opinion on Yoko, but since he later played drums on Plastic Ono Band releases, one could argue that he either had a good relationship with Yoko or did not have any particular opinion.
Yoko is frequently cited as being a major reason the Beatles broke up - although to be fair, they were all drifting apart creatively by the time she started up with John, and John was drifting further and faster than anyone else. Also, the death of longtime and highly influential band manager Brian Epstein deeply fractured the band. In fact, a girlfriend or wife who badly impacts the workings of a band is commonly referred to as a "Yoko" or "Yoko Ono" to this day.
