Ah, I was wondering if you would notice the sarcasm ;-) Apologies, you are right that it isn't really very constructive.
Anyway, I really think that she was trying to reassure you by saying it was her sister. I think that was her being sensitive to your needs. I could be wrong, but I really think that to get anywhere sometimes you have to take the risk of looking for the best in someone.
If she was concerned about your feelings and trying to be open and supportive with respect to the phone call, don't underestimate what that would have cost her. Her disclosing acknowledges that you have good reason to be suspicious. My guess is that would be a pretty big deal for her.
And yes, I think it is still a good idea to empathize with her pain, because in the long run that helps YOU. This doesn't mean letting her off the hook. And, it certainly doesn't mean dismissing or repressing your own feelings. But it means being able to extend some genuine compassion to her AND to realize that she is not trying to hurt you, as misguided as her actions are.
Finally, you are 100% right about rebuilding trust after an A. When you are both there and that is clearly the project that you can talk openly about, when you can openly express your needs and desires for the R, then I personally think the totally open book policy is the way to go. In any case, I agree that her ability to validate your fear, insecurity, and anger concerning fidelity issues and your lack of trust, as well as her willingness to actively work to resolve those problems are key to a successful reconcilliation when you are both at that point.
And, of course you aren't perfect. That's a good thing, I'm not sure who would be interested in an R with a perfect human being, lol.
