The culture I describe is one that exists between close and loving friends. The realistic culture you describe and one I'm fairly acquainted with is one I have with acquaintances or enemies. Tell the truth fast and hard so you don't take a hit for something you're innocent for... its colder and with the expectation that they're your enemy until proven otherwise. Brian and Yuna were obviously close. They're hitting themselves with this. I don't think judging from Brian's tone that he considers Yuna an enemy. Which means he needs to really think about what he's doing; I think he's gotten so emotionally involved he's not thinking straight.
You mention that Brian is entitled to telling his story. Absolutely. This is not about telling his story. He's told it. Its about continually defending his story and making sure his story wins out which is not consistent with his statements that he loves her (well technically it is so I guess I should backtrack on this). His grievances > her pain right now.
Basically, those who will believe Brian will believe Brian is not a liar. Those who believe Yuna believes Yuna is not a liar. Those who are like me will wait. Those who don't care won't ever care. No need to keep defending point for point is what I'm saying.
Entitlement to speak has nothing to do with my point. Legal, civil, cultural rights is not my point. I am saying Yuna and Brian should NOT be talking in LEGAL terms. That is about AS LOW ON THE RUNG OF RELATIONSHIPS that you can go. That is how I deal with my worst enemies because I don't love them enough to reach out to them.
I was born and raised in America my entire life. I am well aware of the "legal" rights we have. The fact the word LEGAL RIGHT is even in this discussion is a SHAME. I do not talk with my friends quoting legal terms and I should hope most of America does not either.
I won't be commenting on this anymore because I doubt it needs to be rehashed and its obviously ruffling some feathers. Because, you guessed it, won't make a difference. I'm probably guilty of talking about this too much already. Bad me! Bad!

(Edit: Not trying to make fun of anybody, just trying to lighten the mood).