Separated but SO wants to still live together

After 10 yrs of waiting for him to figure out his career while i worked, Ive decided to separate. Hes verbally and emotionally abusive. If I was a confrontational person then physical abuse would def be a factor.

I want to move out and have the means to do so, but he doesnt want to get rid of his precious cars so hes trying really hard to convince me he knows what he needs to do to fix our issues even tho he has had years to do so.

Im nervous to finally tell him im not living with him after our lease expires in sept because idk what he may do out of anger. He told a mutual friend that if i dont cooperate by going to counseling and live together for another year then hes gonna fight me tooth and nail for custody, claim abandonment etc. However FL is a no fault state and ive been taking care of the fam for over 10 yrs. I had a lawyer consult and was advised to file for divorce.

Some advice ive recieved was to move out behind his back. Others advised to tell him as soon as possible and have a friend there with you. Ive started using the gray rock method to see if he will want to live apart. Idk what to do.