Palomino by Danielle Steel

Summary
Samantha Taylor is shattered when her husband leaves her for another woman. She puts her advertising career on hold and seeks refuge at a friend's California ranch, where she loses herself in the daily labor of ranch life.

Here, she discovers the healing powers of trusted friends, simple joys, and hard work. She also meets Tate Jordan, the ranch foreman, and a tumultuous relationship ensues.

When Tate disappears and a fall from a horse changes Samantha's life forever, she is confined to a wheelchair and must look deep inside herself to finds the courage to begin again.

Now, fighting the battles of the handicapped, she finds new challenges, new loves, and even the adopted child she's always longed for.