Lady's Rock by Sue Lawrence

In the Scottish Highlands, in the early 16th century, women are traded as pawns in marriage. Catherine Campbell is one such bride: betrothed to Lachlan Maclean and sent from her fine home to join him on the Isle of Mull, to bear his children.

Lachlan proves to be nothing like the man of Catherine's dreams, and she is forced to resign herself to enduring life with him for the sake of duty. Then the day arrives when he threatens to take away the one thing she can't sacrifice: her daughter.