Dear Cynthia and David,
Just yesterday I read about two of my favorite people finally getting together as a couple. I immediately had to show the news to Harold, who is also excited about the event. I wanted to sit down and send off my congratulations and let you know that Harold and I add our best wishes to the many you will receive.
If, after the wedding, the two of you would like to go with us on a 'double date' for lunch sometime do not hesitate to call. I am sure you will have lots to do both before and after the wedding. Call if you need anything.Fondly,