struggling to understand

I'm hurting and struggling to understand why my husband is thinking that splitting our family is the best solution to our problems. My husband has faults, his self-admitted one being that he is selfish. But i dont understand how someone as good as he is and as well brought up as he was, is so selfish that he's not willing to take the steps necessary to keep the wonderful family he has together.
We have two beautiful children together.
I cannot begin to grasp what life he feels he is missing that he is willing to throw his wife and children to the wayside.
I understand that we argue alot. But it's workable, people have to learn to get along. I have shared the negatives that I need to work on in myself on here. He has things that he needs to work on. Isn't family worth that?

I dont want to be a single mom.

I dont want to lie in bed alone at night.

I want my husband to love me and cherish me.

He is a good man, he just has some growing up to do. So do I. But that doesn't mean that, because we have differences and aren't very good at working those differences out at the moment, we can't grow and learn and make a better family together.

What does this teach our children? What am I supposed to tell them when they are old enough to understand?

When my husband determines to be a wonderful husband, he IS wonderful and amazing and so kind and caring and loving and everything any woman would want in a man. He is very handsome.
When my husband determines to be a wonderful father, he IS wonderful and amazing and so much fun! Absolutely a perfect match for our children.

All I can do right now is pray. All I can do is give this to God. And that is so hard to do. We as humans have the need to say or do that 'one thing' that will make everything better. In this case, I need prayer. Dont get me wrong, I have things I need to work on in myself to make myself a better person, but in the case of marriage...prayer is it.
I pray that God will put people into my husband's life that will help him grow into the man God desires him to be.

I love my husband!