Welcome to the Recovery Forum...you aren't alone in any of this.
You may not be able to change his behavior but you can begin today to have a life of your own. Sneaking out when your back is turned? Pretty childish if you ask me.
You are powerless over another person...that is true...but you also have choices. You can stay one day at a time while coming here, reading, getting educated about addictive behavior and making a plan.
There are power posts at the top of the anon forums that are worth a read, along with a reading list. Do you have a library you can use?
Please make yourself at home here...we have been where you are and many still are.
Hugs,
JT