Advice on divorce

Shakawanna

I’ve been separated from my husband for 4 years. He moved on before I did and is currently living with his new gf. I just recently got in a relationship a year and half ago and things are getting serious. We have four children together and he won’t divorce me. Also I moved to Atlanta 2years ago and he still lives in Arkansas. What would be the best option for divorce? He is not cooperating... which I don’t understand why? He has moved on already 🙄🙄