It’s time to write this shit down. I have not totally clarified these thoughts in my mind, and I doubt that I can communicate them in an optimal manner here and now, but I’ll begin my attempt anyway.
Before I begin: a warning. If you read and understand this theorem, you may never want to be involved in a sexual/romantic relationship ever (again). If the reasoning holds up, then the conclusion is that sex or romantic relationships are inherently anti-rational, unavoidably non-consensual (and therefore unethical).