Lilac Mills
The Husband's Secret by Liane Moriarty

Blurb
How well do you know your husband?
My Darling Cecilia
If you're reading this, then I've died.
Happily married and the mother of beautiful children, Cecilia has the perfect life . . . until she finds the envelope. Written in her husband's hand, it says: to be opened only in the event of my death.
Curious, she opens it - and time stops.
John-Paul's letter confesses to a terrible mistake which, if revealed, would wreck their family as well as the lives of others.
Cecilia - betrayed, angry and distraught - wants to do the right thing, but right for who? If she protects her family by staying silent, the truth will destroy her. But if she reveals her husband's secret, she will hurt those she loves most . . .
The Husband's Secret is about the things we know, the things we don't, and whether or not we ever get to choose. Above all, though, it's about how we must live with the consequences of our actions - whether we like it or not.
Review
In some respects we could all say 'there but for the grace of God...' in terms of making a mistake (like fiddling with the car radio and taking your eyes off the road for a second) but this mistake is catastrophic. Unplanned, unintentional, but terrible nevertheless, and is stays with John-Paul throughout his life, affecting not only him, but his family.
The feeling of a circle completing itself stayed with me through the latter part of this story, and running all through it is the weighty hand of doom, fate, predestiny - call it what you will. The inevitability of some things and the surprise of others had me biting my nails, sometimes knowing I was right, and hoping I really wasn't.
Then there is Rachel's terrible pain to contend with.
This is an emotional read, a hard read too in places, but I found it all the more riveting for that.