Mom Affairs

A friend and I, both divorced moms with kids, somehow managed to start having a bisexual fling together just for fun. And it was fun having some rather marvelous and uncomplicated and very active sex and enjoying just being women together.
Well, that was three years ago, and now I would have to say that she and I are having a rather serious lesbian love affair. Our kids, we both have a son and a daughter, of course know that we are good friends, but we have managed to keep our lesbian relationship a secret from them and from everyone else.
In one more year our kids will all be off to college, and Dee and I have decided that we want to move away and to live openly together. I’m sure that we are not the fist divorced moms to find ourselves in this situation. We are just not sure how to break this news to our kids. Does anyone out there have any advice to offer on how to do this exactly without it being like dropping a bomb on them?