Here is my take.
Mind you this is just my opinion( having been on the recieving end of lies and cheating) and IMO there is physical lies and cheating and emotional lies and cheating.
Your looking at this as a well I can be miserable and keep my mouth shut, or I can risk it all and talk to her/them and possibly lose one or the other or both.
I suggest that you take a look it from outside the box.
Is your wife happy with the level of her relationship? Is F? Are you?
Does honesty rank high enough on the list of qualities that you want in your life or the life of the loved ones around you, to endure the pain and commitment to working through it?
How long will this last before you inadvertantly do something( because its who you are) that hurts the others? (IE: the email thingy)
I know your scared to open this conversation up again. ( read back up to LR's post). I was the one that freaked out and went ape shit .I was the one that felt like I was the only one gettign fucked over.. The gods honest truth is once she was direct, honest, and still loving of me we soared to heights I never thought possible. LR stated she was ready to accept that I would walk. To be honest that still may happen but what wont happen is that I will never ever ever stop loving her cause of her honesty with herself and with me..
Good luck my friend, The good things in life are never easy
Peace and Love