He is a grown man and responsible for how he takes your leaving. You don't have to know how to do it, or if you're doing it "right" as long as you stay separated from him.

Don't meet him to talk, at home or away from home.

Don't go to your home with him to pack your things, unless you are accompanied by the police.

Don't allow him to be close enough to touch you, no matter what.

Good luck, I know how hard it is, but leaving again is harder than leaving and staying gone.