I can totally relate brother, I was married 19 years...divorced 5 years ago, I thought my life was over and the world was ending.
My son is 13 now and he comes over almost every Friday and stays until Sunday. I enjoy the time we spend, even if I have something to do or if I am busy, he's always there with me helping and learning.. like building things or working on the car.
It's all about spending time!!
I never thought that children could mean that much too me. I am glad that you feel the same. Yes, we are Not all bad;-)