If this is a recent thing and you don't intend, as you say, to act on them, then maybe don't think of being too hasty. It is possible they might subside after a while and things will calm down, then there might be no need to mention them at all. If you really feel you need to tell her or that they aren't going away and you have the kind of relationship where you discuss these things, then I guess the choice is indeed yours. On the whole though, if it's not something that is hurting her or needs to be said, then there is no real reason why they can't stay in the privacy of your own head if that's what you decide you want.