Tell me something, is it really too much to ask that you call your significant other before meeting up with friends? Not call to ask permission (I would never suggest that) just to say, "hey, I'm on my way to meet so-and-so at the mall." Wouldn't that be informational? Courteous? Thoughtful?
Would it be too much to assume that the other person would think you were, oh I don't know....possibly trying to hide something when you don't tell them that kind of information? I mean, why else would you purposefully not tell someone you're meeting someone unless you don't want them to know? Especially if said person had previously gone into great detail (while maintaining the utmost composure) that she (or he) would appreciate knowing that bit of information??? Wouldn't you then realize that it would be the nice thing to do to keep the other person from thinking such thoughts?
Or would you tell that person that they're being paranoid and claim that you are the victim because they don't trust you?