You screwed up and he left. You are still in love with him, what you did upset him but this is not the end of the world, maybe it was your fault, maybe not. The dream of ending up together married and starting a family is not impossible. So here is what to do to pursue your dream:
1. Tell him you are sorry for what happened and for not being together anymore
Suggest you can try being a couple again; this is a mistake which can be considered a lesson. Maybe starting fresh is possible.
2. Remind him of your good moments spent together
Invite him for a date at the same place you met for the first time. Tell him about the times when everything was great and you were a nice couple.
3. Tell him about your feelings
Tell him you still love him and you want a future together. If he is responsive to that, you have a good chance of being together again.
4. Seduce him
It is not honorable but it works sometimes, because he will remember how it was when you were together. If you end up in bed, it is even better.
5. Be happy if he wants only to be friends again
This will remind him how good it was to be together and there is a good chance he thinks about the great time spent as a couple.
6. Write a letter or an e-mail
Tell him how much you miss him. Be sure to include recent photos of you as a couple.
7. Send a gift to his parents
Tell them how much you miss their son. Do this only if you are sure his parents like you.
8. Invite him for dinner at his favorite restaurant
When you are together be nice and kind. Tell him how sorry you are and say you are open to communication. Emphasize the idea you do not want to pressure him in making a decision and tell him he has as much time as he wants. After the meeting, do not contact him, it is his turn. If he wants to be a couple again, you can be sure he'll do it.