May I add a couple of comments? None of the items you listed as possible examples of cheating would be considered such in my relationship with my boyfriend—a 20+ year relationship, undefined in conventional terms but falling somewhere between ‘open’ and ‘polyamorous.’ The only item that I consider to be cheating is dishonesty, and that would be a deal breaker for me … whether it is in the sexual realm or any other.

My other thought: yes, we can and should respect our partner’s boundaries even if we don’t share them. But if it is truly a loving relationship, I would hope that both parties would ask themselves, “If this is something that gives my partner pleasure, why do I want to deny it to him/her?” Perhaps the answer isn’t insecurity. Perhaps there is a really good reason. But it remains a question worth asking.