irst, a bit of disclosure. My first marriage (yes, I've been married twice... I know) ended because my spouse had an affair. I spent a lot of years carrying around a lot of hate in my heart for her. Even now when I look back on it I can't help but feel a twinge of resentment. We had agreed upon a couple of things and she chose to turn her back on that agreement.
The relevant piece of information for this thread is what we had actually agreed upon. We agreed that neither of us would have any sexual interaction with anyone but one another AND we agree on the fact that sexual interaction is viewed as a holy event. Now, we never actually discussed the second part but it was pretty obviously part of the agreement; it is why so many people respond with wild arm waving, gnashing and waling, and violence when someone cheats and why this kind of irrational behavior is so widely accepted by common society.
Both of these agreements are totally daft in my current worldview. When I look back on my first marriage with my resentful eyes I recognize that she flagrantly broke my trust BUT I try to mitigate my emotional involvement with that fact by recognizing the "trust" was built on a faulty thought process.
My solution going forward has been to entirely let go of the idea that another persons sexuality is my business. It is decidedly NOT my business. I made my ex wifes sexuality my business and she did what people do when that is the case... she cheated. Was my broken worldview wrong or was her rebellion from it wrong? Both? Neither, maybe. I would say that my worldview was childish, her agreeing to it was childish, and her inability to tell me that she didn't want to function that way anymore was childish. We were a couple of dumb asses who were living by utterly flawed thought processes.
To me, this translates to "I do not feel that I deserve respect and trust. People will always cheat in monogamous relationships so everyone might as well have non mono relationships so there are no rules/boundaries/agreements to keep. It reminds me of the kind of things habitual cheaters say and those that are habitually cheated on.