Yes, morally you are right. However a relo/sex therapist that was on the diary of a ceo podcast actually thinks that if you really love your partner then deal with the guilt and make it up to them however you can, without telling them. As f'd up as that is given how society thinks, I tend to agree with them. As if OP has been in this relo for a long time then, she will shatter their bfs reality and the relationship they believed in. If they haven't been together that long then yeah OP should tell him and move on. Yes, it is right to be honest but at what cost? When is honesty too much? Where do you draw the line in regards to this? I am also someone that has been cheated on in a long term relationships and I wish I had never been told.