I was brought up in the Church of England, went tyo Sunday School, joined the choir, was confirmed by David Shepard (which I'm really smug about). Meanwhile my Dad dabbled in Spiritualism, and read people like Blavatsky and Jung. He tried to talk to me about this but I was a teenager and knew everything, so I dismissed it all out of hand.
Later after working in the Middle East I began to feel cramped inside my Christianity, but I continued with it, at one time trying to get ordained (they turned me down) always looking for the bigger picture and reading everyone I could find who was doing the same.
Then a few years ago I picked up "The Final Barrier" by Reshad Feild (sic). This was my intrduction to Sufism. I was struck by how sophisticated the conceptual vocabulary was. For example, in Christian writing you read about the "self", especially diminishing it. In Sufi writing you see the "self" taken apart and analysed, you see the function of each part, and how to gain mastery over it without losing your essential identity. It was as though Christians heard rumours of a lost continent, but Sufis had been there, made the maps, set up resorts and sent the postcards home, and that was seven hundred years ago.
I was initiated into the Sufi way a couple of years ago and have been following it since then. But I don't feel I've left Christianity, I just understand it better now. I'm currently reading some of the Christian and pre-Christian mystics to explore these ideas some more.