Husband and Wife have a Child.

Wife works part-time and serves as Child’s primary caregiver.

Husband is laid off from his job. No replacement job is in sight.

Husband and Wife are struggling financially.

At Husband’s suggestion, Wife increases her hours on her job to full-time, temporarily.

Husband then suggests that he stay home with Child, to save substantial daycare expenses, temporarily.

All perfectly plausible and reasonable, of course.

Watershed: In families with a child under 5 years old in which the wife works, twenty percent of husbands are the primary caregiver of their child. And nearly half of all fathers are at least equal contributors to rearing of their children.

Three, six or twelve months later, Husband tells Wife he wants a divorce … and primary custody of Child.

Wife refuses to agree to that custody arrangement. She insists that she has always been Child’s primary caregiver – until Husband’s recent layoff.

Since Husband and Wife can’t agree, visitation and timesharing issues will be decided by a family court judge after a trial.

But the family court judge may actually put a great deal of weight not on the timesharing and visitation arrangement that was in effect for the longest amount of time but, rather, on the relatively recent and current visitation and timesharing arrangement – especially if it seems to be working well and the Child is doing well. In other words, if it ain’t broke …

So it is that that casually undertaken agreement for Husband to stay home with Child could suddenly, unexpectedly, turn a lot less temporary – maybe even permanent.

Moral of the story: despite the recession and cultural shifts taking place around them, Wife – or Husband, as the case may be – should consider very carefully before making any big lifestyle change requested or suggested by the other parent that affects primary caregiving of their child, even on a short-term or temporary basis.

The request / suggestion may, of course, be made in total innocence.

But the ultimate impact a bit down the road could be dramatic and decisive. And potentially haunt them until their child’s eighteenth birthday.

Read more in this CNN Money news article: Stay-at-home dads: More men choosing kids over career.