Just hang in there and lean on God. Get him involved in church. There is nothing you can do about the OW. Whatever you uncover he will just find a way to hide it better. I'm not sure if he just feels bad about what he is doing or that he still loves you however you have to open up the line of communication. I suggest looking into a Weekend To Remember. My W really didn't want to be there but during that weekend the lines of communication opened up. It was the turning point in our marriage. Dont get me wrong its not perfect but we work on our issues. Hang in there and stay prayerful during this difficult time. Grow closer to God and he will help lead you through this time.