Tin Man by Sarah Winman

This is almost a love story. But it's not as simple as that. Ellis and Michael are twelve-year-old boys when they first become friends, and for a long time it is just the two of them, cycling the streets of Oxford, teaching themselves how to swim, discovering poetry, and dodging the fists of overbearing fathers. And then one day this closest of friendships grows into something more. But then we fast-forward a decade or so, to find that Ellis is married to Annie, and Michael is nowhere in sight. Which leads to the question: What happened in the years between? Excellent condition.