You should post this on the attoney forum, but here’s what I know to be the case: Once a spouse has left the marital home and taken up residence elsewhere they no longer legally have access to the marital home.
You should let him know, in writing that you are changing the locks and that he is no longer allowed to be on the property without your permission or invitation. Have it sent certified mail and keep a copy. If he calls, hang up. Or let the children answer the phone. Don’t talk to him on the phone unless it has to do with the children. As soon as an argument begins, tell him that you are not going to argue and hang up. Do not let him pull you into an argument. If he shows up after you have given him this letter, then contact the police. Do NOT answer the door until they arrive. You can tell them that you are separated and that since he does not live there and you have asked him to leave, you would like them to remove him. If the children are there, the only thing I can tell you is that send them to their room until the mess is over. Talk to them. Explain what you can to them and leave it alone. Get a recorder on your telephone, if you can hide it from the children, so that you can record when he calls and instigates an arguement.
If you have been separated this long and you have allowed this behavior to continue, it may be difficult to change it now. But legally, it is your right to not have your ex so involved in your life, in your home or contacting you just to keep everything stirred up. Take control of your life.