After we are born again, we all do turn away from God at times just like Peter when we are drawn by our lust for the things of the world. We do not lose our eternal salvation, however we do temporary lose our fellowship with God until we repent.
Do people lose their faith?
There is a sense in which if we believe Jesus is God, then how can we continue to do ourselves
harm by staying in sinful behaviour, and if our hearts change we want and enjoy other things.
So equally if we stay in sinful behaviour or return to it, we are hurting ourselves and the Lord.
There comes a point when we are so closed down and shut off, like Tina Turners song, "What
has love got to do with it", we have no living relationship and faith.
So I am suggesting that sin destroys our faith, it destroys our ability to trust God will forgive
us and leads us to a place where we say, it is all pointless.
What I am trying to say, is walking in Jesus is walking with an open emotional heart.
To continually do ourselves and others harm, causes us pain, which we can only survive by
becoming hard. Once we are hard, we do not notice sin or care about it.
Paul described this condition as reaping death.
So the living plant of faith lives by following and obeying Christ, walking in love.
It is damaged and hurt by the evil we do and the denial of the hurt we bring.
Is this a fair summary of things in Christ?