Well, what you've been doing for over two years hasn't worked, right?
Then it needs a change of plan, one that has the best chance of success. An EA of this type can go on indefinitely, years and years, if it isn't forced apart- either by choice or circumstance. Your wife obviously can't or won't make the choice- so circumstance is your only hope. Circumstance can take the form of the OM breaking it off- but again, that is unlikely. So what can you do to force a change in circumstance? Well, the plan I outlined above would certainly do that, while at the same time preserving an image of you being a great guy in her mind. Another tactic might be letting her family know of your wife's two year affair and ask for their help in restoring your family. Your wife does not want them to know because they would not approve and would put pressure on her to stay away from the OM (something she does not want to do).
Whichever way you go, a game changer is in order. In my case, I forced a circumstance to create change, which, in turn, prompted her choice to end the A and return to the marriage. I should have done it earlier- but I did do it, and I'm glad for it. Essentially you are just speeding up what's going to happen anyway- she's either gonna stay or go. Why suffer another two years to get your answer?
Also, don't date while (if) you are separated. Separated is not divorced. There is a very good chance of reconciliation during separation. Dating might destroy that chance, will not help you in a divorce/custody case, and will not make you look like a hero in your kid's eyes. Just my opinion.
