You are not going to like what I am about to write, but please read it and think about it before you get even more upset.
I am sorry to inform you but we don't hold pity parties. We offer advice and support neither of which are easy to give or receive.
You ignored what to many people would be warning signs. He was rushing the relationship and you knew it. He wasn't communicating. You were the bright spot in his life giving him all the support you could. He gave you a platitude, "He said I was the only positive thing in his life and didnt wanna put off the happiest day of his life". Any time someone pushes for a quick marriage or talks about getting pregnant BEFORE a PLANNED wedding there are huge red flags flying on the hurricane winds.
He was running away from the pain of his parents' illness. He tried to bury his fears of death in planning a life and a marriage. That doesn't work. Sooner or later the person wakes up and realizes that there is no escape from reality or quick fixes for the emotional turmoil and trauma. He has to face his fears.
You have to let him go. You can't make him come back. You can't make him want to be with you.
Yes, it hurts. Yes, it seems sudden to you as you perceive it at this moment. If you read what you have written as though someone else wrote it, I think you will begin to see that there were warning signs.
It isn't going to be easy. It will be painful. No one will tell you that the hurt and pain go away in an instant. As you already know, it takes time and very hard work to heal. I am not telling you anything differently than I would my son, daughter or friends. I don't believe in wallowing in self-pity because that energy can be put to better use.