My ex isn't getting the message

I have called off our relationship, been together for 10 years. I called it off in June but he doesn't seem to get the message he still lives under my roof is still lives with me like we are together I've explained to him so many times but he always seem to think that I'm sleeping with someone else because I won't sleep with him or I'm cheating on him how do I get it through his head he has understand that we are done. we have three kids together I'm happy to co-parent with him I love him but I'm not in love with him he seems to think that my feelings are just dropped off overnight when I've told him back in June that I don't feel the same anymore and he still continues to think that there's somebody else and your feelings cannot drop off with someone after you've been with them for that long I need help