Dear Stephanie!
This must be really hard right now, and believe me, I know this feeling. But don’t give up on yourself, and don’t run away from the pain. The pain means that you are an emotional being that is capable of love and of letting someone close to them.

I don’t think anyone can take that pain from you right now, you will have to go through it, accept and understand that it will take some time to gradually get better.

However, there is a subjective thing I want to say:
You write that its such a good match and everythings perfect, etc… But even if your life goals seem to match up, there is more to a relationship! He does not seem to be a very stable person, or capable of dealing with his own emotions. And it is not your responsibility or even within your power to fix him! Do you really want to be with a person who – unintentionally but nonetheless – pulls and pushes you away again and keeps hurting you? Your hope that this will change is noble but is it realistic?
Could it be that therefore he is not the right person for you as things are? Should you start to protect your own boundaries?
Another question you should or could ask yourself is: Why are your emotions so strong? It is completely normal to feel sad and to be afraid and feel really shitty… but is there maybe something else? How did you feel before you knew him? Where you ok with being on your own? Or are you using the relationship to cover up some deeper wound that is now being ripped open?

(I hope I’m not putting too much or the wrong things on you right now, these are just the questions I am facing myself right now, having split up with my boyfriend after 6 years because I was an anxious wreck with nervous breakdowns, worn out by being pulled and pushed away again … I don’t know your guy, but my personal advice right here would be: Start taking care of yourself, respect yourself, create healthy boundaries for yourself and don’t make yourself dependant on a dream of a relationship that clearly does not exist the way you want it to…)

I wish you all the best, try to take care of yourself as best as you can… (It helped me to be aware of my feelings and always ask myself: What is the very next best thing I can do for myself? A cup of tea, sleep, eat, meet friends, cuddle up…) I hope you will feel better soon!!