This was the book I just listened to, it covers the Let It Be and Abbey Road albums in a lot of detail, and looks at there relationships and how they broke up. It's very thorough, I found it for free on Audible... https://kennethwomack.com/books/beatlesbooks/solid-state-the-story-of-abbey-road-and-the-end-of-the-beatles/
RE: B is for... The Beatles - Abbey Road