Step child that manipulates and lies

I have 3 step children 12, 11 and 10. The 10 year old has his mother wrapped around her finger to the point of lying about anything sang and everything To get his way. The 10 year old had gone so far as to say I Choked him and it turned into a big mess w the authorities. He finally admitted he lied about the whole thing. When his mother and I set up punishment for him lying or whatever the case may be at the time i stick w it and she changes the rules and let's him off without any discussions w me at all, what do I do??????

Shane, if the child's mother won't and doesn't support you when it comes to her kids then you're wasting your time. Her disrespect for you is being mirrored through the 10 year old's behavior to you. It doesn't matter what she says to you or organises with you concerning him, her actions are speaking if and when she changes the rules and reneges behind your back. She's trusted you in the first place to go into a relationship with you but know she's betraying that trust by her actions concerning her youngest. She trusted you to assist set up punishment for him with her but that's her responsibility and hers alone. Take your thoughts further and look into your relationship with his mother. That's where the problem is.