We have 3 kids together, one being a 10 week old. The relationship has been toxic for 3 years almost. We have been together 5. Our 4 year old son acts out and hits me when I try to explain that mommy and daddy are going to be separating. My daughter who is 3, just gets quiet and allows her older brother to bully and mistreat her (she saw me allow it from her dad) how do I do this without hurting them?