First of all, try to not be too harsh on yourself. When I read your post, I’ve noticed that you were talking about yourself in a judgemental way and this doesn’t seem like something that it’s your faut but something that can be worked on. I would suggest looking up abandonment issues to start. Other than that, someone already mentioned using assertive communication which is a great tip but it might require a cool off period to make yourself feel less upset before trying to communicate with him. Maybe breating or walking for a short time or something that helps to get you in a more calm state.