What about telling her, but not telling her. What I mean by that is some statement like "Boy if you weren't straight I would ask you out" in a joking manner. That way you kinda get it off your chest but are less apt to threaten the relationship. Your realizing that you are feeling like this is great by the way, good use of mindfulness. Other than that I would tend not to feed into it either, and give yourself some space if need be.