She is the one that is CHEATING ON YOU. Now quit taking all of the blame and lets get a plan together. The first thing to do is to bust up the affair. And most agree that the quickest way to do that is expose the affair. Again, look up Puppy Dog Tails and ask for help in this.
Time to quit whinning and get started making you the better option and to not live in an open relationship. You are better than that>
