Realisation can come in a number of ways, sometimes because of an unloving elder , or a new belief that is untenable or just by thinking things through and realising that it does not work.
Rarely however does that cause a sudden break, not if you are really in it. You are entangled in family and friend relationships, there may be congregation responsibilities to hand over. In short, you have to live a double life for a bit to sort these things out and then it is best to slowly ease off and drift away so as not to attract attention.