I am confused by your situation because sometimes it sounds like your H has chosen you, and then sometimes I read it as he's still with her. So I don't know if you are at a place where this suggestion will help you.
If you two are a couple, and other woman is just orbiting like a moon, then I suggest that you two go to a Retrouvaille weekend. If you have good results, like at least 75% of the people who go to the weekend, it will bond the two of you as a couple. And he will see that she is nothing to him. Look on the website http://www.retrouvaille.org for dates and locations for the weekends. You can read Limbo and EdieMarie's threads to see how it turned around their rocky relationships in only 2 days. If you could get him to agree to go, this has the potential to end the torment that you have been living in, and make him see what he has been doing. All without you telling him about it. It could be the best spent 2 days of your life.