Yoko was not much appreciated by any of Lennon’s friends. She was seen as mentally abusive of him. Looks like she was spiritually abusive of him, too. It would stand to reason that after a walk on the witchy side with Yoko, he would move back to his spiritual roots as he matured.
For a lot of Christians introduced to the occult, it is very exciting at first. For people born and raised Christian, Jesus in their Spirit is a normal state of being. When they flirt with occultism, the spirit of evil which is presented to them as good, can be felt and noticed. It’s exciting. Until it is not. After they get back in touch with the spirit of God, then that is exciting and new, until it’s not. These folks seek a spiritual fix like an addict seeks heroine.