Most Helpful Guy
I think the word cute when applied to other adults has a different connotation than telling someone they look nice or have a gorgeous or beautiful feature like eyes. Cute sounds like you're flirting, and you shouldn't be flirting if you're in a committed relationship. But there's no problem with saying "Hey I really like your hair" or "I just wanted to say you have a great smile". As long as it's just that. Not fishing for a response of gratitude or anything, just honestly paying someone a compliment.