There are bits and pieces here that are not on the other thread...so since I commented on those I will comment on these...
As NOP said...don't involve Missy at all...I didn't realize that you gave her his passwords to look at HIS email...really, it is one thing for you to "snoop"...quite another to have your friend do it for you...this to me is a betrayal and if I were on the receiving end of this I would be furious...
Whether you think so or not...you are playing games here...changing passwords, then changing them back but wanting to discuss this in counseling???...What do you hope to accomplish with that???...show him you can keep secrets from him too???...really, you both need to grow up here...and you need to start with yourself on that...you have children that are watching...is this how you want them to model their relationships...read around and you will find others commenting on how their spouse's family yelled and played games...it really is setting them up for problems when they grow up...
Well that is all I have for this portion of your drama...I do hope you can figure this out...but for the most part...it all starts with YOU