Sel,
In my experience, young people will often leave to sow some wild oats, but in their heart they still believe the doctrine.
This type of JW is a a common source of the sad critter, the "Unbelieving Mate".
The prodigal JW will start to date some poor, unsuspecting non-witness. Dating leads to love, love to marriage, marriage to children.
Now this person who left the organization to experience some freedom becomes terrified by the overwhelming duties of parenthood. They feel compelled to offer their child a sense of purpose, morality... a concept of faith. They feel called for the sake of their children to be the persn they always wanted to be. Since they were JW, and taught to be contemptuous toward every other concept of faith, they naturally return to the fold.
Now their poor spouse, who thought they simply married this nice, upstanding person who just so happened to formerly be a member of some wierd religion that they don't know much about , suddenly finds themselves married to... SUPER WITNESS.
oops. ouch. ugh.
Not so hilarious hijinx ensue.