A few years later, the car's a bit less shiny, a bit tatty round the edges, perhaps, doesn't go quite as well as it once did; anyway, you've done quite well for yourself, you can afford better, something that shows off your success. So you trade in your old car and buy a nice shiny newer, better one.
Is that how it is with wives? Is it how it should be?
As a rule of thumb, if you think Jesus is setting down a command, a law, a line you mustn't cross - you probably haven't understood what he is talking about. That certainly applies to what he said about divorce (taking that passage from Mark slightly out of sequence). It begins with the Pharisees seeking to 'test' Jesus: "Is it lawful for a man to divorce his wife?"
We know, from other writings, that this was a live question at the time: not so much the question of lawfulness - that was just the opening gambit - but the question of what was sufficient reason for divorce. Can a man divorce his wife (it was always that way round, by the way) for any reason he fancies (like changing his car), or is it only for specific reasons, such as persistent infidelity or - 'obviously' - infertility.
The Law of Moses is, at first sight, clear: "Moses allowed a man to write a certificate of dismissal and to divorce her". Incidentally, the point of that 'certificate of dismissal', or Get, is that it states that the woman is free to remarry.
On the other hand, the Prophets seem divided: "For I hate divorce, says the Lord, the God of Israel," as Malachi puts it. But there are also prophets who talk about divorce as the appropriate response to extreme infidelity (generally as an analogy with Israel), for example in Jeremiah: "For all the adulteries of that faithless one, Israel, I had sent her away with a decree of divorce."
Jesus would have been expected to do the rabbinic thing of bouncing around these quotes (and others, especially Hosea), along with precedents and other rabbis' teachings, before coming up with a balanced judgement about when it was right for a man to divorce his wife, and when not.
Jesus doesn't play that game.
The underlying assumption of the question is that wives are possessions. Either possessions which can be freely traded, like cars, or functional items whose job is to provide (legitimate) children ... dynastic enablers, if you like. This assumption is (in)famously reflected in the tenth commandment, not to covet a neighbour's house, wife, slave, ox or donkey.
Jesus comes at the issue from a different angle - for Jesus the starting point is the beginning of the Bible, in Genesis 1, where God creates humanity in his own image, male and female together, to work in partnership looking after his world.
Women are not 'things' to be possessed but colleagues and companions to be joined with in true partnership. There are families to raise, together, communities to build, together, and a fallen world to heal, together. That's the way marriage was meant to work ... sometimes it does and sometimes it doesn't, but God's intent should be the starting point for discussion.
Divorce is allowed in the Old Testament for when this breaks down, for 'hardness of heart' as Jesus puts it. The commitment, 'contract' if you like, is for lifelong faithfulness to one another, and is before God, so don't treat it lightly.
But 'hardness of heart' is as real today as it was in Ancient Israel. Violence, abuse, abandonment, and extreme unfaithfulness can all destroy a marriage - the wrongdoing is not the certificate of divorce, but the (possibly many) factors which caused the breakdown.
Technically, the most faithful wife, once divorced and remarried, breaks her original commitment when she first sleeps with her new husband. Then the first contract is broken, annulled, and a new contract established, hopefully one which will last, bringing healing and purpose - the way God intended marriage to be.
I usually try not to criticise other church traditions on this blog, but to me the Roman Catholic church's take on divorce and remarriage - refusing communion to the new family - is simply heartless and evil. The new Pope has suggested he wants to change this, but to have treated people that way at all is simply wrong.
So if Jesus isn't giving a rule here, yet another burden, then what is he saying?
Firstly that marriage is a precious union of equals, a lifelong commitment before God. Do everything in your power to make that work for good.
But do also recognise that we live in a fallen world and relationships do go wrong. If so, the Bible gives us a way out. Divorce should never be taken as an easy option, but sometimes, because we all have hard hearts, breaking the old covenant and starting anew, before God, is the only way forward.
God loves you and is on your side, trust him with all that you are.