I can sum this story up in two words: GROW UP!
James and Ruby are first and foremost friends. The friendship develops into a marriage of familiarity rather than convenience. Ruby's always been in love with James, but James has seen Ruby as nothing more than his childhood friend. James doesn't see Ruby as a "woman" and instead turns his sights to Jo, Ruby's father's wife (yeah, it's complicated) when thinking of a woman. After Ruby finds James in a compromising position on their wedding night, things run downhill from there, and their sham of a marriage clings by a thread. Their friendship in tatters.
Ruby resigned herself to being in a loveless marriage but devises a plan to make herself happy while enduring it. Little does Ruby know, James has started to see her as the woman she is, but it could be too late. Ruby only desires one thing from James to remain his wife, a child. Rather than keeping that knowledge to herself, Ruby tells James, causing their already fragile union to collapse completely. James and Ruby aren't even fooling James's parents with their charade of a marriage. Even on his death bed, James's father knows things aren't what they seem despite the show they've put on.
Ruby's Passion is a series of misunderstandings, followed by the repeated childish behavior of James and Ruby, sunk this one for me. I don't recommend this one, but if you can handle it, proceed with caution for tantrums, childish brooding, and outbursts every other page.