What do you think about the suggestion that he may have a sexual addiction? Especially if he's still doing this stuff....even though he's been caught and it's created so much pain and conflict....that sounds even more like an addiction.
One of the signs of addictions is that even when an addict knows how destructive a certain behavior is...they don't stop. In fact, most of the time...they escalate because it takes more and more to get the same "rush" or excitement.
Here's a line that really troubles me:
he also was sending intamate emails with a few girls he works with
This is a huge red flag that his activities have gone farther than just online. These are people he knows...not some anonymous strangers from the Internet.
When you confronted him with the information you found...what did he say besides the denial of other infidelity? How has he been treating you since you found out?