People pick up and abandon beliefs all the time. I can't help having been baptised a Christian, but when I came of age I freely chose to stop believing in that religion--as have (independently) my older brother and my father (and Mom's kinda hanging by a thread there with her vague talk of "spirituality"). It took effort and money to remain Christian and at some point I decided it was no longer worth either.

Is this necessarily an easy choice? No--but that was exactly my point.