Marek's argument did not, in fact, involve the things he'd said before. At least, he didn't think it did - he still wasn't entirely sure exactly what he'd managed to convey to his twin of what he'd been feeling, considering he'd felt rather reticent on the issue. But somewhere along the lines of pursuing Felixa, he'd realized what was really bothering him about his sister's relationship.
"It's not about specifically what he said to me or - er, what you were doing," he said, with a slightly irritated hand gesture that indicated he was still somewhat awkward talking about his sister's sex life, even though he'd accepted that it existed. "It's just - Melinda, the way he acted was like he took it for granted that he'd be able to shag you again regardless of how shitty he behaves around you. Don't you think you should be asking for more respect than that, especially from someone you'd even consider being hitched to for the rest of your life?"
He made the peaceful gesture again, and then ran his hand through his hair. "I don't mean that he should be afraid of your wrath if he hurts you, because if you're not emotionally involved, that's not really an issue. I'm not even saying that he doesn't respect you - but he's at least under the impression that he doesn't have to. And if he thinks that, that's because you're letting him think it. That's the part that worries me."