[An edge of anxiety creeps into Robert's voice, making it slightly shrill even though he doesn't quite look up.]

I understand this is d-different... or, by all rights, ought to be different - but I worry, perhaps e-entirely irrationally...

... [Softer, now:] It... is n-not you. Or, at least, I... am not certain wh-why it would be you... I have just never been p-particularly good at phrasing myself in such circumstances, and... the m-more troublesome the topic, the... more my poor phraseology is l-likely to... make the situation difficult to resolve...

[He's already done it even in conversations they've already had before. Even if they've managed to negotiate them...]