Have this trope in your books and it's an immediate way to get your books relegated to the never in a million years shelves on Goodreads. Adultery is an extreme emotional trigger for a lot of people and they will avoid reading anything with adultery in it. It's absolutely understandable to avoid triggers. For years I couldn't watch or read anything with a mother's death in it. By years I mean at least fifteen years.
I have read many mainstream books that included adultery, and it always seemed very formulaic. Husband having fling on the side with glamourous work colleague whilst wife who has let herself go brings up the children. Or how about ignored, bored suburban housewife by workaholic husband meets exciting plumber/ex-boyfriend/neighbour, has one night stand, feels guilty and confesses all to shocked husband who storms out and goes to live with friend, but forgives all in the end. *deep breath* Maybe I read too many middle-class books. I did read far too many bonkbusters in the eighties.
There are many people, whether they have been affected or not, will say there is never any excuse for adultery. They won't read about it in a romance. They don't want to see their characters as flawed. I don't see it like that. I would say there are always reasons people stray. Bad reasons, understandable reasons, plain human failing. These are not excuses, but the reasons. I include them in my stories because people come with baggage, and adultery is one them. Whether people can be forgiven for straying is up to the people who have been hurt by the actions.
The Night Porter is a Bittersweet Dreams book published by Dreamspinner. Therein should give you a clue that it doesn't have a fluffy ending. The language is sparse and the emotion raw. This isn't about the headspace of the two men, and has little time for the guilt. It's about the physical desire of two men, shortly before one of them is due to get married. I don't make the characters villainous. They are flawed, yes. Weak, maybe. But shit like this happens. From the readers who have contacted me, men like/understand Night Porter and women hate it. That doesn't ring true for all of course, before anyone starts leaping on me for making generalisations.
Final Admission approached the subject of adultery in a whole different way. Here I tackle same-sex spousal abuse, the fall out after a serious accident, how protecting someone isn't always the way to help them and yes, adultery. Let's throw in all the emotional baggage we can.
To the outside world, the man who commits adultery is a jerk. In reality James' home-life is with a violent man. His reasons for staying are myriad but all of them tied up with a huge amount of guilt, compounded by the tacit agreement of his relatives. It takes an outsider to cut through the layers of guilt and abuse, and show my character the way forward.
I take a more sympathetic approach, but the headspace is full of confusion and there is no easy answer to get to the HEA.
Hairy Harry, my hero, Peter, was cheated on by his wife. When he meets the first person he had been interested in years, they come with a penis and a boyfriend. Peter has been cheated on; he won't do it to someone else.
Tumbling Blindly is about healing a broken heart and moving on.
Morning Report, the one book that would never, ever feature cheating because Luke would string Simon up by his balls... and that would be just the start.