It seems impossible to rid your mind of these thoughts. That often happens. What if you simply accept that for the time being these thoughts are going to be around?

The thoughts are sort of like annoying house guests; you can't get rid of them at the moment but instead of railing against them you can accept their presence and go about your regular life. In other words, you can say to these thoughts "Oh there you are again", nonjudgmentally, and carry on with your commitments to your wife.