Free Love by Tessa Hadley

It's 1967 and London is alive with the new youth revolution. In the suburbs, meanwhile, 40 year old Phyllis Fischer inhabits a world of conventional stability. Married with two children, her life is both comfortable and predictable.

But when Nicky - the 20-something son of a family friend - visits one hot summer evening and kisses Phyllis in the dark of the garden, something in her catches fire. Newly awake to the world, Phyllis makes a choice that defies all expectations . . .

'Wonderful' Marian Keyes

'Beguiling' Hilary Mantel

'Compelling' Elizabeth Day