My ex was the same way as you and I was more or less like him. I think this is similar to the whole pronoun situation. You’re well within your right to voice your concern or just casually say that you’d prefer if he said “I love you”, same goes for people who want to be identified a certain way Just make sure that if or when he doesn’t and just says “love you” that you don’t scold and berate him for it. At the end of the day it isn’t a super huge deal so go easy on the guy if she forgets