"We'll get used to it. But we'll do it at our own pace."
Love how he used "we" here. Spoken like a true couple. And he shared how he was also nervous to ease her own nervousness. Proper communication (plus emotional intelligence) saves the day once again. It would've been easy to clam up and let her be nervous all day for an awkward date while pretending to be a picture of composure himself, but as her boyfriend it just didn't sit well with him. Besides, it's true that he was nervous.
Rintarou isn't perfect, but "dense" and "insensitive bastard" are labels that will never apply to him. I'd say he has emotional intelligence that is lacking in some male leads elsewhere and this makes him stand out to me.