If S is with his sister, is there any reason you can't stay in a hotel tonight, or with a friend, or with your daughter? Maybe it would be best to have this conversation on the phone, where you might feel more in control? Perhaps this is not an issue for you, and that's good if not.
Remember, you don't HAVE to go home or do anything else, only if you want to. Also, you don't HAVE to talk tonight...you can ask him to delay if you need some time to cool down.
Think about it. Remember, with MLC it's a little different....you CAN set some boundaries and start stepping up, it's not the normal delicacy of WAS....b/c regardless of what little things you do they need to ride out the MLC. You have limited impact in ways.