The Fundamental Things

Becca Hughes Fairleigh has married into the perfect family. Her adoring in-laws are a balm after her troubled childhood, although she's fiercely devoted to her father and brothers. After clinching a national show jumping title, she's content to settle into life as an up-and-coming designer in the perfect house with the perfect husband by her side.
Yates Fairleigh is at the top of his game, married to his childhood sweetheart and gainfully employed with his doting dad. He enjoys their slew of extended family, and when they all start procreating, it gives him ideas.
A horrible secret, a letter from Becca's birth mother, and tensions everywhere make quick work of the family's contentment. Becca, Yates, their siblings, and their cousins choose sides, and their peaceful friendships threaten to explode into an all-out war.