not saying you did, just asking you a question. say someone, say they are even a spiritual mentor to you turns from the faith and rejects Christ, does that mean they were never saved? if so how could they have ever given any spiritual advice? this happens all the time in churches.
At the end of the day I can only chunk it up to the two ideas given.....People who are genuinely saved by faith may fall away due to circumstance such as the death of a loved one, disease, questioning God as to why etc.....people who fall under this grouping fit the first aspect given below and then some who were never saved go out from us because they never were of us.....I will use a personal friend of mine as an example....His name is Darryl and I went to the seminary with him...He was raised in church, saved, immersed, called to preach, educated and without a doubt has given ample proof to his salvation....married, 2 kids, pastored churches faithfully......his wife cheated on him, left him and in bitterness he quit preaching, going to church and as far as I know is still out of church......regardless of his failure and walking away in bitterness JESUS cannot deny himself and remains faithful to his word, his promises and his power to keep Darryl as a saved child of God because the righteousness of Christ has been imputed unto Darryl's account by faith and he has been born of incorruptable seed.....the flip side of the coin....I have known people who came to church with the mindset of "what can you do for me".....they have never shown except for Easter, Christmas and pot lucks, they never witness, they never understand the word, and when the rubber meets the road they fade off to never be heard from again......NO ROOT.......at the end of the day the only one who can 100% know if they are or are not is GOD........
If we believe not (after belief) he abides faithful because he cannot deny himself.......<--written to believers