I don't really have an answer for you... except something a very wise woman I knew once told me. "Kids are very resilient. Like green saplings that bend in strong winds, if you truly love them, then they will be able to weather whatever storms may come."

My two cents, is to be age-appropriately honest about the situation. They may already understand more than you realize. That was the case with my kids.

Not sure if that helps any, but you are most definitely not alone.