I get the feeling he's actually going to realize he really likes miharu here
He wishes he could say "That's right, I am someone who is only able to worry, [but she puts me at ease]" to refer to natsuko, but it's only true for miharu
I think they're both understanding this date and relationship are over, but the therapist is down to help miharu psychologically a bit before they don't see each other again (at least not in a courting way)
The guy has been legitimately helpful to both nozaki and oshiko when he's in his lane as a therapist, plus he's one fictional depiction of one therapist, don't let him turn you off of therapists in real life