The kiss - Danielle Steel

Love, tragedy and hope conspire in Paris, when a kiss between two strangers changes everything.
Isabelle Forrester is the wife of a Parisian banker who has long since shut her out of his heart. She has one secret pleasure: a long-distance friendship with a man who, like Isabelle, is trapped in a loveless marriage. To Bill Robinson, Isabelle is a kindred spirit. Agreeing to meet for a few precious, innocent days in London, they find their friendship changing, and they exchange their first, searching kiss. Time stands still - and tragedy strikes.
A long journey begins - towards healing, hope and dreams of a seemingly impossible future. Isabelle and Bill cling to life. Together they must find the strength not only to embrace the future but to face what they have left behind.