Why should she know? No please I'm not interested in the answer - this is a question you need to ask yourself. Unless you still have feelings for him, then there is no need to speak. Its the PAST leave the past where it belongs. Even IF he loved you (not just saying it or was saying it to get into your pants) he has most likely forgotten by now. Most likely do to forgetting he has failed to tell her. YOU telling her now may result in trust issues, definitely if he forgot or didn't think it was important (most guys do not consider non-relationship love interests to be important enough to mention) could easily lead to a fight between them. As far as I'm concerned your "desire" to tell means you want to stir trouble because you STILL have feelings for him and think that breaking them up is a 'good idea'. I doubt that you wanted her to know, because you would have told her way before she got together with him that there was 'something' between you too. So once again I ask you to ask yourself "WHY she needs to know. --> Yeah I'm sure you will readily say 'no', that's not why - but if you sit there and honestly think about it you most likely will find that you do have feelings for him and in that light your 'desire to tell' takes on whole new meanings. And YES we do do things without knowing exactly WHY we are doing them, until we do them and then think about it and realize that we were being stupid and thinking with our heart not with out mind - but by then its too late, we broke something and its all a bad situation for everybody and we regret ever saying anything (seriously sorry) and end up wishing we kept our f-ing mouth shut. WE ALL MAKE THESE SORTS OF MISTAKES. So my asking you a third time to question why you NEED to tell her is more or less to make certain that you are not going down this road and are not making a huge mistake that will ultimately hurt you.<--