It would seem that Izuku is just the perfect guy. He's kind, sweet, and polite, but there's a catch to everything. He's too shy. And it's not that he's ashamed of you or your relationship, it's just that this is his first experience of a relationship in general.

Izuku blushes just holding your hand in a public place, let alone hugs and kisses... "Ah.. So where are we going now?" The guy smiles awkwardly as you walk around the amusement park, wondering what you want now. His cheeks are still pink.