How do you move on from a womanising alcoholic?

After 20 years with a skirt chasing alcoholic, I have finally seen the light and have separated. How do I move on? How do I get him out of my head? How do I re-establish the friendships that he undermined/destroyed? How do I get my life back as his alcoholism has led to my social isolation? (Friends would politely tell me that they would like to see me, but did not want him around and I stupidly remained loyal to him). We have two kids, so I do still have to interact with him to some degree.