<human>: I was seeing a man for a couple of months a few years ago. He was single and we wound up fooling around a couple of times. 

He disappeared for some reason and stopped answering my texts. I figured he lost interest and moved on. 

He popped up again into my life several months later. He was upset that a friend had died and was very drunk. I told him no. He blew up my phone about how he cared about me, never meant to hurt me, blah blah. I felt sorry for him and let him stay at my place.

I contacted him several weeks ago. He was interested in meeting again and then disappeared.

Curiosity got the better of me and I started searching for him on Facebook. I find out that he has a wife, three kids, and another on the way. He was married when we first met according to the timeline. When he resurfaced, apparently they were having problems.

Now I'm conflicted. I have text messages, even the most recent ones where he swears up and down that he was single and had been single for a couple of months.

Do I tell the wife or how would you handle a situation like this? I can prove that I had no knowledge of anything about his family. I also have emails revealing that he probably slept with other women while he was "single" as well.

I feel bad for the wife because she is about to have a kid, but at the same time he's been whoring himself out and getting away with it while she looks out for the kids.

They have 3 other children, so it's pretty obvious that she isn't with holding sex. They can't all be "mailmen babies".

Several of my friends are telling me to tell her no matter what and others are saying to just let it go and let karma get him. 

I don't know what to do.

Can you provide a brief overview of the text?
<bot>: Found out I was a married man's mistress. His wife is pregnant and he has three other kids. Do I tell?