Is the words "i love you" in a relationship important?

i've been going out with this girl, and she never seems to say "i love you" and i asked her why she never says it and she said it loses the meaning, and i said well it doesn't to me because, because it wouldn't. and she said well thats you. Am i in the wrong for being slighty annoyed for her not saying i love you or do i need to relax a bit? bearing in mind i've heard it about twice in a month