Most Unforgiveable Offense?

Well, I'm gonna state the ovious here, but in some books the hero rapes the heroine in the course of the story _ and that's probably the most heinous thing one could do to someone else. Of course, I must mention Judith McNaught's Whitney my love, Catherine Coulter's Devil embrace and Christine Monson' Stormfire here, but there are other examples, either good or bad. Charlotte Lamb has written several novels with such situations I think.
Now that I think of it, there's another Judith McNaught novel _ Something Wonderful _ in which the hero treats the heroine badly : he deserts her, then comes back and shuns her, then accuses her of plotting behind his back, which leads to the heroine getting shot and nearly dying.

In Patricia Gaffney's To Have and To Hold, the hero is quite odious to the heroine all through the book, including an heart-tearing scene of public humiliation and near-rape by his friends.

I can't seem to think about many books in which it is the heroine who wrongs the hero. There is the trope where the heroine cheats on the hero, for instance in Jo Beverley' The Shattered Rose of S.C. Stephens' Thoughtless.
I would say anything involving hiding a baby from its father is pretty heinous too.

I'm torn, cause I hate Alexei in Brenda Joyce's The Promise because he was petulant, arrogant, hypocritical & a general jackass to the heroine that constantly undermined her worth as a person when he wasn't ignoring her. He never was redeemed for his behavior toward her nor really apologized.

Then there's for its times "ok" but in retrospective really awful Rosemary Rogers book, The Insiders, where the 'hero' leads the heroine's gang rape where it's all whitewashed later because he liked her fighting spirit while being gang raped & that's why he wanted to marry her. That book wasn't at all a romance but it was fascinating with its flaws in terms of the WTF factor. http://www.amazon.com/Insiders-Rosemary-Rogers/dp/0380405768

Of a similar nature to The Insiders and also by Rosemary Rogers, The Wanton is another OMGWTFBBQ book in terms of romance & how the hero & heroine treat one another. I read it when I was 11 so I don't recall all the details but I recall thinking everyone in the books was selfish and nuts. http://www.amazon.com/The-Wanton-Rosemary-Rogers/dp/B000NWRJNQ/ref=pd_sim_b_6

When hero sets up and/or deliberately puts heroine in mortal danger, something like Dane did Marlie in Linda Howard's Dream Man. I think she left him off the hook to easily... I like this book, I remember first time I read it that I was loving everything about it. But now... I must say it was a di*k move.
I just read novel where heroine is a doctor and she is desperate to have baby, she and her husband are trying for years, but nothing is happening. Their results aren't showing anything unusual, he even starts talking about adoption. And then she found some kind of medication that lowers drasticly his sperm count in his purse.He was taking it all along. Maybe author did great job describing how she felt betrayed, but I was really disgusted with him....

Legeartis, what's the name of the heroine doctor book -- do they divorce, forgive -- now you've got me curious!

Balogh is pretty fantastic for making the unforgiveable eventually forgiveable -- can't even count them all. But say Indiscreet, the 5th Bedwyn book, the book that just came out, Christmas Beau (of course, there's a lot to forgive on either side there).

Rape, of course.

Being too controlling is a huge thing for me, too. I remember a time travel romance of some variety where the hero destroyed the heroine's ability to return to her time because "he loved her so much". I hadn't much liked either character before that, but wow, did I want him to die in a fire.

Rape is the worst thing, but I remember in a book--can't remember the title-- that when the heroine becomes pregnant, the hero utterly denies that it could be his and accuses her of having an affair. I believe that it is years later when they meet again that the hero realizes that he was wrong.

I read a Harlequin by Jacqueline Baird, Carmenlire, with that plot. The hero even divorced her and wrote off his parental rights too but when he came back in to her life and realized he made a mistake, he compounded his error by threatening her unless they became a family again. I want to say it was called "Shattered Trust."

The book was Fearless by Diana Palmer. The "hero" (if you want to call him that) was Rodrigo Ramirez. The heroine was Gloryanne. He was a undercover FBI (or something of that sort) and she was a lawyer for the DA's office hiding out in a witness protection situation on a ranch. He did not know this, thinking her a poor ranch kitchen worker.

I cannot nail down just one unforgivable thing he did. It was more like everything he did. He was in love with another (married) woman, flaunted the fact and treated the heroine like dirt. He called her unattractive and uneducated, made crude comments about a limp she had, seemed almost dismissive or derisive about her affection for him, and while he didn't rape her, he did take advantage of her sexual availability, in a "hit and run" sort of way. She eventually resumed her regular life, but with a baby bonus in the oven. When she came to him later to tell him she was pregnant, believing he should at least know he was going to be a father, another woman answered his door. When she told him about the pregnancy, he denied it was his and accused her of being desperate, being after his money, and trying to manipulate him into marriage. Only when, near the end of the book, he accidentally saw her in her role as assisstant DA, polished and professional, did he consider she just might be good enough for him. Arrogant ass. I didn't buy the HEA ending. I was hoping Gloryanna would wise up and tell the arrogant pig to go do anatomically impossible things with himself.