Pillars of Heaven — Leila Lyons

Their desire burned like the fires of hell. They came from the Old Sod to the New World to follow their future and their fate: Liam O'Sullivan and Rory Fitzpatrick sailed westward to the wild forests of the Oregon Territory drawn by visions of wealth and power, driven by passion for the women they couldn't live without...Kathleen, who wed the right man for the wrong reasons, and Sophie, who married the man she didn't love to be near the one she couldn't forget.