I have a 4 year old son and 2 stepchildren (13 and 16). We have them to stay every other weekend, and get along pretty well (although the first couple of years were pretty hellish). My DS loves them, is always very excited when it is 'their' weekend, they are fantastic with him. In fact considering how stressful this step parenting lark can be we are all doing well (touches large amounts of wood). My problem now is that DS is rather a sensitive young man, prone to worrying, and we have been guilty of avoiding potentially upsetting and alarming subjects (burglars, illness, fires, death etc), because we know that he will let his imagination run wild and convince himself that terrible fates are going to befall everyone. So when I comes to the whole step thing we have just tended to state matter of factly "yes, X and Y live with their mummy, we share them, they have another house etc" and then changed the subject. But I don't think I can avoid it forever, and fairly soon I think he may want to know why his 'brother' and 'sister' live somewhere else and have a different mummy. So how do I gently explain the whole divorce? I am worried that once he discovers that mummies and daddies can leave each other (and their children) he will completely freak out. Any advice?