Things I Never Told You — Beth K. Vogt

It's been ten years since Payton Thatcher's twin sister died in an accident, leaving the entire family to cope in whatever ways they could. No longer half of a pair, Payton reinvents herself as a partner in a successful party-planning business and is doing just fine―as long as she manages to hold her memories and her family at arm's length.

But with her middle sister Jillian's engagement, Payton's party-planning skills are called into action. Which means working alongside her opinionated oldest sister, Johanna, who always seems ready for a fight. They can only hope that a wedding might be just the occasion to heal the resentment and jealousy that divides them ... until a frightening diagnosis threatens Jillian's plans and her future. As old wounds are reopened and the family faces the possibility of another tragedy, the Thatchers must decide if they will pull together or be driven further apart.