This whole "I've got a new date", might just be another manipulation tool - the tried and true 'lets make him jealous trick'. She wanted to get a reaction from you and she almost succeeded. If she really is going on a date then she sure moves on fast. You would think there would be a little time to contemplate and feel sad - more proof that she was in it for marriage sake and not because she's really attached. I don't mean to sound evil, but if I were you I'd wish her a good time - that will really surprise her lol. Sorry if this is hard on you.