But what does this mean?
It's something I'm thinking about as I prepare to leave my forties. For me it's been ten years of drama - as usual! - but one thing I've noticed is the way that each decade is marked by different social occasions.
In my twenties it was weddings: fun and frivolous and filled with the hope of happy lives lived well together.
My thirties were overflowing with small children, their christenings and parties and playground antics. There was lots of joy and delight and sleepless nights and wishing that they would stay small forever.
But life got darker in my forties...and some of the most significant social occasions became funerals, of neighbours, friends, and my lovely Mum. So perhaps 'Life begins at 40' is an ironic joke? Bye bye to Pollyannaland and hello to real life with all its unfairness and tragedy? No wonder so many middle-aged people get so serious...
Now someone else I know in another country is not well. And I hate that I can't just pop round to offer comfort, support or help. I remember the pain of a friend of mine who had to deal with the death of someone close to her who lived on the other side of the world. Every bittersweet conversation they had after his diagnosis was charged with the knowledge that they would never see each other again. I am not in that situation but I often think about her.
For my friend, her children's needs had to come first. And so it is for me.
I have to push away the thoughts that fill my head and get on with the chores of the day. Nothing can be planned, because everything can change in an instant. One week the medication is working well and then it just isn't. I wish the magic cream, plasters and nurofen that make most things better in this house would work for him, but of course they won't. I want to offer advice, in fact I want to tell him what to do. But it's his illness and he is entitled to handle it his way. And so I muddle through...