Get out the tissues (for them). Be as strong as you possibly can in front of them. Let your H take the lead. First and foremost, be honest. They are old enough to hear the truth.
I would suggest getting some take out or calling for pizza after he's gone. Trust me, he'll be lightening quick. Then, the three of you can have a big group hug and a good cry. You can answer questions as best you can. From what I know of your sitch, there won't be much you can tell.
