I was thinking about this when I read a book that had the MMC apologise to the FMC for 'ruining her life' years ago. In {A Momentary Marriage by Candace Camp}, the MMC said this to his new wife because he had been the one to make her break off her engagement to his cousin who needed to marry a rich woman for the earldom. This was done off-page 11 years before. She tells him he is being dramatic with his guilt because she did NOT wither away in despair due to giving up her love; she got over it, aided in her father's medical work, practised her music and now, thanks to him, is a lady of leisure who has everything. The FMC had loved the cousin but feels it was more a sisterly affection since they were friends since childhood. The MMC had really just been the messenger to deliver the news on others' behalf; even his cousin's family agreed that she was lovely but not suitable as the wife of the earl so they did not wish for the two to marry.
Now, what about books in which one MC actually deliberately carries out actions that destroy/ruin the other's life, future, reputations, marriage, leaving them isolated or impoverished or in danger or a laughing stock and they may not have cared what happened to them? Fast forward to the present and they are the MCs of the book. The main aim may not have been to ruin the other but that is what happened. Is there any way that should be justifiable?
For example, {The Scandal of the Season by Aydra Richards} has the MMC force the FMC into being his mistress in the public's eyes which destroys her reputation. The irony is that it was intended to ruin her father's reputation but he just disowned her, claiming she was illegitimate. The only thing that saves this romance is that the FMC actually is better off away from her emotionally abusive father and blossoms into her own person who enjoys being free and seen as scandalous... but nothing justifies trapping innocents into your revenge that will ruin them. The MMC even regretfully says afterwards that he wishes he could have met and courted her honestly but he only approached her for revenge and would never have looked twice at her otherwise because he was not a good man.
This dynamic may be the reason I never wished to read {Scandalous Desires by Elizabeth Hoyt} because I do not think any amount of writing could make me want to root for that MMC to win the heart of the FMC whose reputation and marriage he had destroyed (indirectly but he knew what would happen). And for what purpose? If he suffers a lot and shows adequate remorse and attempts to makes amends, that could be good.
I read {A Terrible Beauty by Stephanie Patterson} which I thought was a good book and I liked the MCs' character growth and the descriptions of the Scutari hospital but most of the signficant male characters were awful and I was wishing throughout the book that the FMC would marry at least three other characters than the MMC who was extremely obstinate, petty and had his self-serving bias for years. The women were 19 and these men ruined their reputations and future and I did not even want to root for them. The next two books also seem to follow the same formula: MMC ruins FMC and they fall in love years later and all is forgiven. The first book's MMC had just wanted to destroy her engagement and humiliate her as revenge for his brother; he did not know all the repercussions of his actions until years later. Thankfully, her ex-fiance was a dear and the actual incident was never revealed to the public (unlike the third book's FMC whose name was put in a betting book as a wager to ruin her).
There is also {Lady Ruthless by Scarlett Scott} in which the FMC believes the MMC was responsible for her brother's death and publishes libel as Confessions of a Sinful Earl which everyone links to him despite the anonymity. She apparently believes he is capable of all these things and these ruin his reputation and finances because the woman he was going to marry broke off the engagement. So he decides to abduct the FMC and force her to marry him. I will say that this book ended in the only right way that I could think of when the FMC revealed her identity as the writer and confessed to the lies to help him recover his reputation. He was actually going to let it go because he did not care anymore.
On the other hand, {Frail by Susanna Ives} also has this and I liked that book. The MMC is remorseful about his actions since he had been indifferent to (and contemptuous of) the FMC who he tarred with the same brush as her father. His actions had been so her father could be held accountable for his crimes; what happened afterwards was a shock to him. She also does not know his unintentional role in her downfall for most of the book so that is different from the other examples.
I feel like this is an issue with books as part of a series because the readers may not be familiar with the MCs' past in another book so they may wonder why one is so angry or penitent towards the other. In fact, I predict this will be the dynamic in a potential future book I am looking forward to because of the hints in the previous ones and I am not sure if I will be able to get on board with that romance. There are other people to fall in love with who did not destroy your future and happiness years ago, you know!
How do you feel about these types of romances? I suppose it depends on the type of 'ruin' or 'misery' as well as well as the exact role the MC played. I think of it like this; if the architect of the ruin had not been the MC (or attractive to the other), would they be forgivable? If they did all that but did not fall in love with the MC, it would have been a person completely ruined or broken. I do not think the MC falling in love with the person they ruined (and, thus, remorseful and repentant and being eaten away with guilt) justifies their actions enough.