First of all - I can understand them wanting to see S12 but why in the world would they go over there alone with her? Secondly are you certain S12 WANTS to be there? Thirdly - I would recommend something more traditional as far as visitation. Honestly for us the time initially apart from H was helpful in letting the kids get into a routine and know what to expect. Also, that continuity is important so that they know even if one parent is not there that they have you. This is imperative. Also, I would encourage S12 to come back home. You need to decide what you want. Really. Do you want to stay M and try again or do you want D? Whichever you choose you need to sit your kids down and rationally and calmly tell them. Then you need a game plan so that all of you know what you can expect. As for OW- as I said you should limit all contact with her if possible. In the future if the kids want to see each other why not contact H and ask him to bring the other over or even have them ride the bus after school if need be. These confrontations are damaging.