Problem with a long distance relationship and after-work rides

We're on different continents. My wife works late so her company organised rides for her to get home. Thing is chatting is the cheapest way for us to communicate so we chat for hours. The problem comes when it's time to go home and she goes quiet. I trust her but we and fighting why she goes quiet during this time. I don't mind her getting a ride but as least i feel i deserve a heads up? What am i doing wrong?