when you let someone in on something... that makes you vulnerable in the process.. you are trusting they wont harm you... Or else you wouldnt let them in right? Unless you want them to be the 'judas'.
What I have found is that when you tell someone 'not to tell' they usually do. If you are ever tempted to say 'but dont tell them', you are much better off never engaging in that conversation in the first place. If you do anyways, its because your a drauma queen and lack the discipline.
Yes, it is insulting to some people to say 'but dont tell them'. If that person is tempted to tell them, but put in a bind because you dont want them to tell... You didnt help that person out at all, infact they are set up for failure no matter what they do. Hold back and fight that nagging temptation, or be the drauma queen their temptations invoke.
Same situation as you, you were tempted to tell them (against better judgement {which is why you said 'but dont tell them'}) but couldnt fight the temptation. How do you expect them to do even better than you with drauma that doesnt even effect them?