In my experience, trial separations after an affair almost always lead to a deepening of the affair, at least initially. You are reading the 5LL book, implying that you not meeting your wife's needs contributed to problems in your relationship. If you are separated and not meeting any of those needs, you must realize that she will try to rely on her affair partner to meet her emotional needs.
Also, you have already done an exposure of your wife. Since you have gone this far and contacted the OM, I would suggest you consider contacting his wife. Your wife told you that he claimed he was having marital issues. I would bet this would be news to his wife. Exposure doesnt always work in your favor, but when it does its the scorned wife that is most effective at destroying an affair. I would suggest if you are going to separate, you take this step to destroy her affair first.