I have a pretty negative reaction to scenes like that due to real life experiences, seeing (skipping doesn't really help here) them can put me back in a spot where I'm just feeling really down for a week or 2 afterwards. For me this isn't about if it should be in the game or not, I think you should be able to tell a story how you would like to. I just also think it's important to set expectations about this type of thing upfront. Just saying on the description page "Hey, there is one scene of cheating in a flashback" is all you need to do in my opinion.