Caelen's Wife (Clan McDunnah 1) by Suzan Tisdale

Rumor has it the water on Clan McPherson lands is magical... Rumor has it Caelen McDunnah has lost his mind…

Clan McPherson has known peace amongst their neighboring clans for more than one hundred years. That peace is threatened when Fiona McPherson is made chief after the death of her husband.
Known more for her fighting skills than her beauty, Fiona refuses the multiple proposals of marriage that begin to seemingly arise from nowhere. She may be the chief of her clan, but she’s still a woman. It isn’t Fiona they want, but her land and she’s willing to fight to the death to keep it.
Called McDunnah, the chief of Clan McDunnah, has no desire to remarry. He’s perfectly content to still mourn the loss of his first wife and babe, even if it has been sixteen years. Until he meets the beautiful and feisty Fiona McPherson.