He won't accept your decision. That is part of the overall pattern of utter disrespect. Don't try reasoning or any discussion or explanation. All he will want from discussions/conversations about this is your attention, your energy focused on him. What he fears most is indifference from you.
He will try all sorts of ploys to get back together including flowers, apologies, promises (you have seen this before). Then he may turn threatening or desperate/suicidal. If any threats are made either way, report to the police. It is not up to you to save him from suicide. You need to protect yourself if he threatens you. He may even try indifference, hoping you won't be able to resist contacting him. Don't get sucked back in that way.
Keep your door locked when you are home. Find a third party to get his belongings to him if possible. Otherwise, arrange to meet somewhere public with his stuff, and take a friend with you. Don't take your DD. Make a list of everything that is in the bag/s. Take photos of everything as you put it all in.
If he contacts you by phone, tell him to email you about arrangements to get his stuff regardless of what he says to you. Then hang up. Block his number.
You can make arrangements for him to get his stuff via email.
If he is still sulking after a week, take the initiative and email him to tell him where his stuff can be picked up and when. (You will have arranged a friend to help you in this and can even cc the friend). In the same email you can tell him not to contact you and not to come to your home. It is important if you ever have to seek a protection order that you have a record of telling him not to contact you.
You don't owe him any further contact.
You don't owe him another chance.
You don't owe him a discussion or an explanation.
Don't make the mistake of trying to get an explanation or an apology out of him. Draw a line under this and get on with your life.
Don't give in to any temptation to check on him. Tell your friends and family you do not want any further contact from him. Ask them not to pass on any messages from him.
Feeling sad and regretful and grieving for the relationship are all perfectly natural responses when you make a decision like this and take action. You invested your emotions and time and energy into this relationship. All of the sad feelings will pass eventually. You will also stop beating yourself up about keeping on trying even though the relationship was so difficult.
Try to keep busy and focus on your DD.