Surviving His Suicide/Still Getting Over Her

I've been to a funeral today. It was for a man that I barely knew (his sister-in-law is a good friend), but it's been the hardest to get through. He had a wife and a 18 month old baby girl, all sorts of potential, and family all around him. and he couldn't see how much he meant to everyone. He killed himself last week. He couldn't see how much his sister-in-law depended on him for advice, or how much his wife loved him, or how much his death would affect everyone. He killed himself, and it doesn't make sense.
He had everything but money. Education, degrees from big name colleges, wife, baby, family, and he just gave it all away. He didn't leave a note, or any reason. He fought with his wife, went and got a hotel and shot himself. Everyone blames themselves. His minister, his wife, his brother, all of them got up and said it was their fault. They should have seen, or they should have done more, or they should have been there more. I want to tell them all that it's not their fault, that there was nothing they could do, but I don't know if it would be right, or if they need to believe that to get over it.
His wife hasn't started grieving yet. She still expects him to walk through that door. There's a look in her eye like she's going to punch him the next time she sees him.
It's stupid. I just don't understand what would make him do that.
He was a big man, big and tall, and seeing that casket this morning, I thought, "There's no way he could be in that thing. It's too small. It's a prank." It's stupid, but I expected him to walk out to give his own eulogy.
I just want to bring him back to show him how stupid he was.
It was hard to be there today, not because he was gone, but because his baby is going to grow up with a daddy who killed himself, and his wife thinks it's her fault because they fought, and no one understands why he did it.
I keep trying to justify it, but it doesn't make sense at all. I hate him for what he's done to his family. I hate him with all my heart. It's stupid and he was stupid for doing it.

On another topic... I realized that My ex-girlfriend is a different person. I don't even know who she is. I get to where I miss her, and I start wanting her back, but all I have to do is go to her profile and see that the girl I love is gone. I don't know how I feel about it yet, but it keeps me from longing for her.