my love language is words. her's is touch. what i've found is that, even though we have different languages, it still works because we both respect the needs of each other.
i would also say that if you think you're in a serious relationship, don't hang out with a single person of the opposite sex without your partner or another few people present (like at a party or something in a large group is fine, but not alone at a bar or something)
i'm weird about hanging out with single women, even if i'm not interested in them, because i think its improper while in a serious relationship and gives off the wrong impression.