A few days ago The New York Times carried a very insightful piece about cohabitation that should be read by every cohabiting couple in Ireland.

The number one justification for cohabitation is that it is good preparation for marriage because it supposedly gives a couple a chance to decide whether they are compatible or not.

Alas, the evidence indicates that couples who cohabit first are more likely to divorce than those who don’t cohabit first.

‘Sliding not deciding’ is a reference to the fact a lot of couples basically ‘slide’ into cohabitation. Bit by bit they move into together without necessarily having formally decided to do so.

The author of the piece, psychologist Meg Jay, talks about ‘set up’ costs and ‘switching costs’. The ‘set up’ costs are low in that the couple may have previously lived in two separate apartments and can now share their living expenses.

But once they move in together it can become very difficult to move out because they’ve made such a big emotional investment in the relationship. In other words, the ‘switching costs’ are high.

This can then propel them towards marriage even though one or both might not really want to get married.

Once they do marry, they can quickly discover that it’s not really what they wanted and they then go their separate ways.

Jay makes the crucial point that if they hadn’t lived together at all, much lower ‘switching costs’ would be incurred in the event of a break-up making it much more likely they would pull out of an unsatisfactory relationship in time and not marry one another at all.

She writes: “I’ve had other clients who also wish they hadn’t sunk years of their 20s into relationships that would have lasted only months had they not been living together. Others want to feel committed to their partners, yet they are confused about whether they have consciously chosen their mates. Founding relationships on convenience or ambiguity can interfere with the process of claiming the people we love. A life built on top of “maybe you’ll do” simply may not feel as dedicated as a life built on top of the “we do” of commitment or marriage.”

We’re always being told that young people need to be taught the facts of life. Dead right. How about teaching them some of the above facts?