Your difficulties with your son are not unusual for a divorced mother. Your son is playing you because he can. Almost any 16 year old will misbehave when he knows that his parents are at odds with one another.
Here’s what I recommend you do. First, make a list of five or six rules or him that are most important to you. Then you MUST make these rules clear to him. He shouldn’t be allowed to be mean, disrespectful and must abide by some very simple, common rules of your home. Sit down with him when he is willing to talk with you (when you aren’t arguing) and tell him that you love him very much and because you love him, you are going to be firm. Becoming an adult man requires learning how to be disciplined. He cannot be happy if he never learns self control.
Let him know that you believe that he can follow these and then tell him that if he refuses, certain consequences will follow. Tell him that you aren’t going to fight with him and that these are rules and consequences that everyone in your home will follow (the rules aren’t just for him.) When you have this discussion, stay calm and don’t fight with him.
As you talk with him, he may argue, leave the room, etc., but don’t you leave. If he won’t listen, reopen the discussion a day or two later but don’t let up and don’t yell. Once he knows the deal, ask if he has questions. When you both understand what to expect, you are off and running.
He will test you to see if you are serious so you need to be ready to implement the consequences if he disobeys. He will argue that you are unfair, yell and threaten to run away etc, but don’t listen. If he breaks rules, consequences follow. That’s how life outside of your home works and you would be cruel if you didn’t teach him this. Don’t argue or yell when you take something away or implement consequences, just do it and don’t back down.
Now, he will run to his father’s house and there’s nothing you can do about this. Let him stay there. If he wants to come home, tell him that he can only come back if he agrees to follow the five rules. Here’s what you need to know. After a while, he will get tired of being able to do whatever he wants at his Dad’s and he will return to you. Deep down, kids want rules because rules show that parents care. He will begin to feel that his father doesn’t care about him.
This is tough but you are doing the right thing. Remember, your younger children will grow up to act the same way if you don’t insist that your son behave. Good parenting isn’t for cowards and it sounds like you are not a coward so stay strong!