I am in a situation where my married-to-me spouse cheated on me with our close friend. We are in an ethically non-mono relationship and have always had an agreement that my spouse would tell me when they were interested in someone. We also have an agreement that I not be home when they are engaged in sexual activities with someone. The other day my spouse tells me that they hooked up with our friend on our couch while I was in our room sleeping. Both of them knew I would be upset with the situation if I walked out and saw them, but did it anyway. In the ENM world breaking agreements is cheating. I am obviously hurt by both of them. The irritating thing is had my spouse mentioned interest in them and done it somewhere else or when I wasn’t home, I wouldn’t have had a problem with it. I don't care that they were physical. The betrayal is what hurts me. I have a boundary that I will not continue to have relationships with people who continue to do a repeated act that hurts me. Is it unreasonable to ask them to not engage in a sexual relationship with one another if they want me in their life? It’s hard for me to answer, because I wouldn’t have an issue had the sexual relationship began with transparency and I had informed consent. But now I feel like I can’t trust them to follow agreements and be considerate. Anyone have experience with this?