I'd get back involved in church, and get marital counseling from the church. She's gone off the path, and doesn't seem to realize the seriousness of her actions. If you really want to save your marriage, get both of you back to Christ. I've seen the church save many marriages, including two of my best friends. Man, not so much.
Talk to her. Tell her you want the best for your family, including her happiness. Tell her how much it means to you to start going back to church, and get
marriage counseling there.
Notice how many unuseful replies are on here? You won't have to deal with those from the church, and you won't be judged. Will probably make a huge difference in her life. Don't underestimate the void Christ can fill, especially for her.