Why did John Lennon fall in love with Yoko Ono?

They got acquainted over about eighteen months. He and McCartney sponsored one of her art shows, and contributed a score to a book she compiled about modern composers. She sent Lennon postcards about her events and ideas, and sometimes letters. When he was in India, they wrote more regularly, and he began getting up early to collect the mail before his wife saw it. He said later it was while he was away in India that he started thinking about Ono "as a woman, not just an intellectual woman".

After he returned to England, his wife went to Greece with friends, and her husband was in Paris on business, and Ono visited Lennon at his home. They took LSD together, listened to some of his private recordings, and used them to make one of their own. (This came out later, as the "Two Virgins" album.) Lennon realized she was someone "I could really be myself with", and who inspired him like nobody could.