Don’t want to be married anymore

I have come to the slow realization over many years that I don’t want to be married to my (good looking, responsible, employed, moral, good father, smart) husband. We have been discussing things along the way as they have evolved so he is not in the dark. This is not what he wants. He is sad about it. I am also sad about it, but what I feel most is guilt. Though I intellectually know I can’t make anyone feel a particular way, I don’t believe it in this situation. I still think this is all my fault/I have failed somehow/why can’t I want what I have/I am going to ruin my husband’s and my childrens’ lives. And that this is selfish.
I can’t sleep at night. I perseverate about the future–the kids, the house, the car. I have a constant pit in my stomach.