text: There was really no need for this to escalate as it has.  You could have just told her you were going to be spending the week showing some old friends, who are a couple, round your country.  She has picked up that there is something wrong and now the two of you are at odds with each other.  Had you been upfront with her and told her what was going on, the ball would have been in her court as she would have had to trust you.  I think if you want still to be with her, you will need to explain to her that you were showing some old friends round (say they are a couple) and that you were not sure whether to tell her or not, since you used to date the female half of the couple, a long, LONG, time ago.  Even if you do think she was totally in the wrong, I think it would be politic for you to apologise nicely to her for not having trusted her to trust you.  I think it would be very difficult for her to answer that one without looking bad herself.