Here's another subject bound to raise questions. Marriage is a core value of human society - although that raises a question: What is marriage? And I don't mean legally - I mean the union of two people into one family.

When we got married, life was comparatively simple. We were in a predominantly Western Christian culture and didn't think too hard about it. (My wife certainly didn't understand the worse part as she does now.) Our ceremony included what I now believe is the core of marriage (but used archaic language). It also included cultural additions - not in themselves bad, but largely irrelevant. After reaching my own understanding I checked the first page of results of an internet search, and found a lot of arguments – some of which were opposites - and definitely strongly held. For example one view was that having sex is marriage (fully backed up by Bible verses), while others said or implied that clearly wasn't the case.

So what is my understanding of marriage now? It's when two people "agree" to “leave” their parents and to “cleave” together (in traditional terms), or in ordinary terms, two people agree to come together as a new family unit. Everything else is extra – although I think the “agreement” should where possible be public, allowing family and friends to show their support.

Both parts are important. Leaving their family also includes their family letting go - not an easy thing for parents. Without leaving parents, it's impossible to be intimately united with the new spouse.

To be clear intimate is not about sex. Sex is a real and intimate part of "marriage" in almost all cases, but contrary to what some say, sex does not equate to marriage – it's basically a seal on marriage. It occurs as part of marriage, and marriage and sex are both God's ideas. Sex is just a wonderful part of a "marriage" relationship.

Our modern view has changed vastly. We had become accustomed to thinking of marriage in terms of Christian culture. But if we go back before Christian times, people still formed families. Before then of course we had the Jewish religion. So I looked back before that - before the man Jacob, later known as Israel.

Jacob's father was Isaac. Isaac decided it was time for Jacob to get "married" - but didn't want him to marry a girl from the cultures around them. (This is not saying don't marry outside your own culture - he had specific concerns about nearby cultures.) So he sent a servant to the area he came from to find a girl. She agreed to come, and they journeyed home. When they arrived Isaac took her into his late mum's tent. No ceremony, no fuss. Both had agreed to the "marriage", although they hadn't met each other. And they formed a family - from which the Jewish people came. Kiwis have for some time recognised de-facto couples as "married". That does not sound all that dissimilar to Isaac and Rebekah.

One difference in many cases is there is no initial decision by the couple - it just "happens", a bit at a time. "Marriage" might be said to apply from the start - although in many cases one or both partners lack the commitment necessary in a marriage. In such a case when couples decide to wed, there usually isn't any significant change - although some might argue people (particularly males) may reduce their effort put into the relationship. Some people never marry, while others decide to make their relationship formal. Either I am very slow (which many believe), or there is no clear pattern of changes brought about by a ceremony.

Whether a couple goes through a traditional ceremony or not, they may or may not agree together to leave their families and form a new family unit. Even when they agree, they may not agree at the start that this is their family - come what may. I consider myself fortunate that my wife stayed true to our agreement, despite being tested by some of the things I've said and thought.

Many people believe a "marriage" is a 50/50 partnership. Initially, I thought this seemed a fairly natural case. As with many things, I now believe I was wrong. Worse this belief is part of the widespread breakdown in families. When two people agree to a 50/50 relationship, what happens when one partner is so pre-occupied by something that their effort falls below 50%? While we might think of this in terms of work and family, I have another more personal issue.

Health reduced my effort significantly - and for the best part of a decade. During that time my wife carried me - capably and without fuss, even giving me a kidney to restore my mind to nearer full function. Had she stuck to a 50/50 split (and I have no idea if we are even close to a 50/50 split), we would not be together today.

In my opinion, marriage requires both parties to give 100% to have the maximum chance of surviving. Partnership sounds sensible, but if it stays as just a partnership, it will never become all it can be. I encourage everyone "married" to give it their all - 100%.

And for those interested in another perspective: Five facts about marriage that Christians need to know…