So very sorry OP....

.... Breaking up is one of the toughest situations that we all have to endure in our lifetime.
The pain is so strong & it can seem like the end of the world. I know as does everyone else on here. Nothing sucks more.
That being said, you need to move on from this person so that you can fully heal. By having any form of contact w/this guy will only postpone the healing process thus taking it much longer than it should to feel better.
Remember you are suffering a huge loss here. It's just like a death. A death from your dreams of building a strong future w/this person. As w/all losses, you need to properly grieve for your loss. There are no short-cuts here, if you try to take one, you will only be hurting yourself much more in the end. Don't do it.
For now, cease all communication from your ex. There may come a time in the future when you can both be friendly w/each other, but now is not the time.
Also, it is normal to still harbor strong love feelings for him. Sure, you know it is not the right relationship for you, esp. for your long-term goal...But that still doesn't make you fall out of love overnight.
Of course you still love this man, he was a very important person to you for four years. That is a huge investment of your heart.
And remember, getting over him is not a progressive journey. You will backslide at times, thus feeling you have taken twenty steps backward.
But there is light at the end of the tunnel. It just may be a long + difficult path to get there, but you will get there, I promise you that.
Remember to take good care of yourself in the process too.
(((( Hugs ))))