I found my wife's boyfriend's wife (his third wife...and mine wants to be #4). We exchanged email and chatted for a while, never talked on the phone. She has no interest in staying married to him, btw. For the record, wife's BF & his wife live together, about 300 miles away.
Advantages: - I learned a lot about him, what makes him tick, his past, weaknesses, strengths, family situation, x-wives, etc. - I was able to craft two email messages that I sent to BF that had info that was hurtful to their relationship. She helped me "bake it in" so as not to appear obvious (in hindsight, I regret sending the emails...I do not recommend doing it). - It was nice to have somebody to talk to, as I made a commitment that I would not tell anybody of the affair. - It was nice to have a female perspective on things I was doing. - I was (and still am) lonely. She filled a void.
Disadvantages - It was becoming clear that BF wife wanted more from our relationship than I did. She had designs on me, that's for sure. - She was feeding me info that was tantamount to me snooping. She had an unbelieveable amount of info. - She was distracting me from DB'ing. I lost focus. - Because we never talked on the phone (chat & email only), I was never sure if I was chatting with her ... or him .
I cut-off contact about a month ago and have no regrets. In the event our D becomes final and I have moved on, I may ring her up. We have a lot in common, and although I don't think we will ever have a serious relationship, we would have a good time together.
Bottom line is that I grew weary of her telling me the fruits of her snooping (she makes it an art...). As Yoyo says: "be prepared for more than you really want to know."
If you decide to initiate contact, have a list of things you want to find out, or hope to accomplish. Get it done, then break off contact.
Warning: Be very careful. Both of you are vulnerable to an EA or PA. You are both emotionally fragile, and you may find yourselves leaning on each other too much. I ended contact when I detected this occuring.
