The traditional concept of marriage is in a chronic state of decay.
Historical wedlock fundamentals are corroding, and the metamorphosis is intensifying.
There was a time when matrimony ushered in a sacred and enduring contract in which couples stayed together, literally for better or for worse, regardless of ensuing compatibility complications.
That was before the baby boomers, who as a group considered divorce to be a wholly acceptable alternative to spending one's life with an objectionable partner. The result was the "Gray Divorce Revolution," which caused a generation of children to witness parental divorce as virtually a way of life.
According to Susan Brown and her colleagues at Bowling Green State University, the divorce rate among boomers has been "astounding" and has doubled over the past two decades.
Over two-thirds of boomer divorces are initiated by wives, and researchers suggest that is because women have become more assertive. Boomers who divorce tend to be less well-educated and those in their second or third marriages are 2.5 times more likely to divorce.
The children of the boomers, the so-called Generation X, or "latch-key kids," grew up experiencing absentee parents and domestic storms between feuding parents.
Those early turbulent times, coupled with the anguish they suffered due to parental divorce, shaped their mindsets away from marriage and toward cohabitation. That was the solution favoured by the notoriously narcissistic Generation X, infamously self-reliant and autonomous, strategies that precluded commitment, so far as possible, to a "significant other."
"People of this generation are more likely to find and receive emotional support from friends than committed romantic relationships, hence the term 'urban tribe,' " explained researcher Anne Warwick. "They live together in group houses with extended families (rather than committing to one other individual)."
Having children is not a major aspiration among many Gen Xers, because children do not fit into their quest for a commitment-free lifestyle. Cohabitation avoids the necessity for marriage-like commitment.
Whereas in marriages the test is whether or not each partner can master the task of taking care of the other, in cohabitation, the reverse is true. The test is to determine whether or not the other person can fulfil your needs, not you fulfilling theirs.
"They shack up and have kids, but don't marry," Warwick reported.
It is all part of the "what's in it for me?" Gen X mindset, according to psychologist Wade Horn.
Of those Gen Xers who do marry, one-half end up divorcing, 20 per cent of them in the first five years of marriage, according to the Centers for Disease Control.
According to Pamela Paul at American Demographics, Gen Xers who cohabit prior to marriage are 48 per cent more likely to divorce, compared with those who do not cohabit first.
Generation X spawned Generation Y, whose members had largely given up on the shacking-up practices of their parents and opted instead for hooking up. For them, even dating is too much of a commitment, an intrusion into their freedom. Many favour hooking up with individuals encountered online through social media.
The hook-up culture of Gen Y stems from a desire to find "self-fulfilment and individual happiness" without commitment, according to psychotherapist Richard Boyd.
"The hook-up culture is uncharted territory," explained researcher Susan Walsh.
"It has replaced traditional dating on college campuses; the hallmark of the hook-up is the clear understanding that the encounter will be free from any expectation for further contact."
"It is designed to avoid the possibility of commitment," she added.
According to researcher Timothy Reichert, Generation Ys do not want to give up single casual-sex lifestyles.
Boyd cautioned Generation Ys intentionally avoid "available monogamous relationships" in favour of hook-ups because they do not want to be pinned down by commitment complications.
Robert Alison is a zoologist and freelance writer based in Victoria.