"I was in the airport, leaving Chicago. We had just spent however many days together and we were texting and somehow it came up, like, 'Oh, shall we get married?' We're like, 'Yeah, OK,'" Cavallari tells E! News
in an upcoming interview that will air March 10. "And then he sent my ring in the mail. So I actually had my ring sitting at home for a couple of weeks before I put it on."