Completely tasteless on her part. Doesn't she know you'd probably see it? How old is she?? What you did wasn't wrong, although it is a little old fashioned. I have gotten to where I usually will skip the Mr. and Mrs./Ms., and just write "John and Mary Smith" when I address things. But I hardly ever address things to two people anymore. Usually it's just a birthday card to one person. I will admit that it does bug me somewhat when mail from a business comes with "Mr. and Mrs. John Smith" - especially if it is from a church that we have visited. That's an instant "We can cross that church off our list!" red flag for me.