How do you break the news about a break-up/divorce to the families of a couple?

My (ex-)boyfriend and I have been together for three years, but we are currently in the process of breaking up (and have been in this process for the past several months). We still live together and will continue to live together until July, when our lease expires. (This is going fine; we’re still friends.)

In any event, we both come from families that are very, very family-oriented, loving, and involved. Our families live in the same city, but the two of us live 8 hours away from them. We visit them for Thanksgiving and Christmas, and they come to visit us a few times each year.

Before we moved away, we saw them regularly and usually together. My parents love him, his parents love me, and they love each other. They’re all so thrilled to get together and think we’re the perfect couple and have always been very excited about us being together. Our families are now close even with each other, and our past two Thanksgivings and Christmases have been completely combined with our extended families! Everyone is all so happy and probably expect that we’re going to get married in a few years…

Our families still have no idea about the break-up. We are absolutely dreading telling them because it is going to absolutely devastate them. Even though we were broken up, we went through with the (already-planned) combined extended family Thanksgiving dinner this year and feigned the existence of our relationship. Our parents still constantly make comments to us (via phone/email) about how lucky we are to have found each other. Both of our families have already purchased Christmas presents for the other side, and Christmas plans have already been made. We’re going to have this last Christmas together and break the news of the break-up at some point after the holidays.

Given how close our families are, how much they love us being together, and how devastated they’re going to be, how should we go about telling them? How long should we wait after the Christmas festivities? What medium should we use to communicate the bad news? How should we begin the conversation? Please help!