Humans are strange and complicated creatures, so it makes sense that when you put four ultra-creative, super-talented, ridiculously imaginative musicians in a room together, there's bound to be some conflict. In the case of The Beatles, there ended up being a lot of conflict — and that means that even though it's Yoko Ono who frequently gets blamed for their honestly inevitable breakup, that's not actually the case. Not entirely, at least.
What happened was more along the lines of a perfect storm of trials and tribulations that the band just couldn't weather — starting with the death of their longtime manager and massive disagreements over who was going to replace him. Add in more disagreements over their direction, individual members who wanted to nurture their individual talents, arguments over who was going to get their songs on albums, stress from rampant drug use, and yes, the added pressures of Yoko Ono's appearances on the scene and in the studio, and something just had to give.
Source: DB Kelly/grunge.com