In the crime-fiction corner of my new favourite shop, R has chosen three books he'd like to buy. Over in graphic novels, I'm picking out an X-Men comic for my elder son, worried that too much exposure to superhero skills and bulging muscles will make him grow up to feel inferior.

We are still in a different city, waistbands now straining a little as our bodies try to burn up all the good food we've eaten in a week. This gorgeous bookshop is our last stop before the airport. I've been scanning its shelves, picking presents for the children and gifts for myself. After kitchenware floors in department stores, bookshops are my favourite way to spend a couple of hours, and with R – after we've talked more on this holiday than we have in a decade – a silent stroll around this shop is perfect.

I spot the monochrome spine of The Alcoholic wedged in between Batman and Spiderman. Jonathan Ames, its author, is a name I recognise and remember as being brilliant, and finding such a book while not looking is like discovering a £20 note in a scrumpled receipt.

If certain books could talk to me, this one would most certainly shout the loudest. "Buy me! You'll find things inside that are all about you and your husband's lives, and all the damaged, crazy people you've known and the mad, embarrassing things you and they have done."

Before I've even opened it, I tell R he should read The Alcoholic. I have an odd compulsion to tell people to do things I have yet to try out myself: with R, it's a sort of parental goading, the type my mum used on me all the time when I was a child, a ploy to get me to do things she had once wanted to do herself: "You used to love dance. Why not try out the tap class at the civic hall?"

When I advise R, I think I'm doing it out of love. But really I'm bossy and feel that whatever I'm recommending (passively, aggressively, sometimes both), will improve his understanding of life.

R looks at me and sighs a plaintive sigh, as if to say: "Read it first, then when you're not looking I might pick it up, read it, love it, then pretend not to have read it because I don't want to give you the pleasure of admitting that I've enjoyed something you recommended."

I read The Alcoholic on the plane journey home. It is a darker tale than I would have imagined, but funnier in parts than I could possibly predict. Ames describes being the victim of a disease without actually playing the victim. He gives us the straight-up version of what it is to live in a body and mind that – when intoxicated – ends up as something he doesn't own and can't control. It is an often hilarious, sometimes heartbreaking story, rather than a limitless outpouring of grief. And the details, when I compare them with R's experiences, are all too familiar.

As he sleeps beside me, I want to nudge R awake and say: "See this bit where he stays in bed for three days and drinks himself towards death? Remember last August?"

And then there are a couple of times when Ames's good friend tries to help and suggests he goes to an Alcoholics Anonymous meeting. Ames toys with the idea, but never goes.

There was a time in our house when I treated AA like the doctor. Every time R slipped into a state of wretchedness, I suggested he went to a meeting. My voice became my mother's when she "suggested" that I go to dance classes. And like her with me, I kept on and on, until R finally capitulated.

I wanted him to tell me how much they helped, how enjoyable they were. It's only now that R tells me he went out of a duty to me, rather than a duty to himself. He may return one day, but if he does it will be because he wants to and not because I told him to.

R's honesty now is admirable. Of course, deep down I'd love him to be singing from the same song sheet as me, stepping into the comfort of group therapy in wood-polish-scented church halls and out-of-hours classrooms – because I still attend Al-Anon meetings regularly, and find them an invaluable support.

And yet, as we hit the rippling runway on a bright summer morning, R sober on a plane for the second time in his adult life, I think: "This is progress." I undo my seatbelt, not quite resisting the urge to slide The Alcoholic into R's bag when he's not looking. But at least I understand that R's recovery is his: it will always be his and never mine. So I can read all the books I want, do what I want to do, go where I want to go. But I can't always expect R to come with me.