I would beg to differ, in the reluctant route or any other route, they were living by the rules that they both agreed to in their wedding vows when they married (that's assuming they had some sort of traditional marriage) When they agreed to try out an open relationship, all their old rules were thrown out. Unless they mutually agreed upon a set of "new rules", any sex with anyone else wouldn't be cheating.
As for your relationship, I can't answer your question, but IMHO, beg forgiveness and agree not to do that again. People tend to forgive when asked to, likewise, mercy and forgiveness, are good principles to live by. They put the humanity into being human.
In the Ethan reluctant route (depending on your choices) assuming they had conventional vows. She does break the vows of "Love Honour and obey, forsaking all others" therefore she has cheated and (again dependant on the players choices) she does admit to Ethan that she is cheating on him because when she asked him for an open relationship (cuckolding) he doesn't agree, she does it anyway. I fail to see how that is not cheating.
Even if he does agree to Cuckolding whilst its not traditional cheating it is still cheating in my view. He makes it clear that he doesn't want to see her having sex with others but she disregards his wishes and forces him to watch and humiliates him while doing so. She even fuck's Darrel in their marital bed and gives up her anal virginity to him in said bed.
I will say that I am probably getting muddled up with what happens in each route, there is at least 10 different routes and I can't remember exactly what happens in each individual route. I still think however that in any of the Ethan reluctant routes (job/no job, Ethan cheat's or doesn't cheat) it still involves some form of cheating.
Look I love all the routes in this game they are very well done, I may not agree with all the routes but it doesn't stop me from playing all routes. Where I get frustrated is people will assume that because cuckolding is being portrayed as humiliation and cheating all be it with the other partners knowledge that is what cuckolding is in the real world, when it really isn't. There has to be a lot of communication between the husband and wife, IF something happens that either party don't like then they respect their spouse and not do it or discuss and compromise.
As for my scenario
![Frown :( :(](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
it was 9 years ago) I didn't view it as cheating at first because I assumed (wrongly) that the same rules applied weather I was dressed Male or female. Only having it explained to me by someone who was neutral to the situation did I understand how it was cheating. My wife did forgive and we have learned from that experience and we have grown alot closer to each other and this year we will be together 11 years, married 8 years.