I would ask those saying if someone "stops believing" they lose salvation. Could you ever "unknow" now that you know? What I mean is that, at least in my case, God made something that was not there before. I could let my flesh win, and from time to time it still does, I can even get angry at God when I am being petulant, but now that I know Him, how could I ever "unknow" Him?
Even if I wanted to, it is His power that saved me and His power that keeps me. I know it does not come from me.
Here is my answer:
I believe that God loves and woos His children; He gives them all they need to be saved and to live for Him: He walks with them, He makes available to them His power, His love, and His majesty! He becomes a friend, a confidante, and a wonderful Lord and Saviour.
But never will the Lord force allegiance or service for His kingdom! His method is love and trust.
For myself, I know that I have the moral capability to reject Jesus. I have in me the same moral capacity that the worst men (Hitlar, Stalin) in history had! I am not better than they were. Were it not for the grace of God, I would be there too!
I thank my Redeemer, Saviour, and Lord every day for redemption! I believe in Him; I cling to Him, and I love Him!
But for me, I know that I still have the moral capability to reject Christ and become a "Judas"! Do I plan to? Absolutely not!
Some day when I get to glory I will revel and forever live in the direct presence of my Redeemer who loves me so much! Praise be to His name!