My best friends ex husband....I need some insight! ?

Are you kidding me? Do you think you are living in a TV soap opera? You will never make this work! You can't be friends. This will soon completely explode in your face. Best advice i can give is to not make an effort to see or talk to her because if you do it will end badly. Cut your losses and be with your guy. You knew what you were doing when you did it, as you seem intelligent. You are just a sh!tty friend. Sorry, it's the truth.