Dishonest partners

My wife has been in contact with another person for quite sometime as I had to travel a lot. I know the person's IP address but not his disguised mail ID. I am sure that my wife and this person has been exchanging email. I want to find out the other email ID of my wife and the email exchanges. Can I find out the email exchanges? ( I know the IP address of the other man as well as ours)

Email addresses and IP addresses are two different things. SMTP email clients (like Outlook Express) and HTML email (like Yahoo, Gmail et al) work entirely different ways. The only way you can do what you're trying to do is to know what service she's using, her user name and password. You might be able to identify what service she's using by entering the IP address in the address bar of your browser but you can't get into her account that way.

welll once you've got the IP address of the other person
you can hack into his email then his computer
get all the information you want
his email passowrd the data on his computer
and you can monitor the chats between him and your wife
you just need to be familiar with Hacking tools!
im sorry man I know how that is and you should've paid attention to the things that matters the most but once u know she's cheating tell her that straight to her face and see where will it leads you both