It's time for you to let go of him and concentrate on your marriage, this relationship won't take you guys anywhere. Have a serious talk with him and ask God to help you out of the relationship. It won't be easy but God will see you through.

tell her how u feel about her, text it if u can or email her but let her know how u feel about her. you took her by surprise and that's why she's reacting that way, don't give up on her because according to your writeup you've known her for a long time and she will be a good partner to u. u should have told her of your feelings long before now. goodluck.