Was this email out of context like he says or should I worry?

I found a message on my boyfriends phone going back and forth between him and another male colleague. My boyfriend was saying that some girl sat in his lap and she was pretty but that the only goddess was another womans name of another colleague. His male colleague response was that my boyfriend would not have a glass of wine with the one that sat in his lap but would have a glass of wine with the goddess colleague. My boyfriends response back to this male colleague was that the goddess said to my boyfriend that the male colleague didn't ask her to have wine, and that the male colleague had a wing man that he had asked the goddess to have a glass of wine and that he has no secrets. I took this as since the male colleague didn't make his move, then my boyfriend did.
My boyfriends response to all of this was that nobody sat in his lap and that was just a joke because him and his colleague joke all the time about the girls and that they wouldn't give him(my boyfriend) the time of day because they were too hot. He basically said that the whole email was a joke...like lol and that it wasn't serious. What he told me then was that the male colleague is married and the goddess is married and that they are having an affair and that he is trying to get his male colleague to stop having this affair. What I can't get over is that there was no humor in the email, no haha or lol remarks and it seemed quite serious to me. My boyfriend said that I took this way out of context because I only entered in on the last part of the email, how odd that all of the other emails before this one was erased...how do I know that there were any other emails that would prove to me this was just a joke? What I saw in the email was that a female was sitting on my boyfriends lap but yet he had a glass of wine with another. What is the humor in all of this because I can't see this. He says that he understands how I would misinterpret all of this. He basically tells me that the whole story is reversed and instead its really the male colleague that this is about...turning it around. The whole thing doesn't make sense to me and he says that I just don't understand the male humor back and forth, which I don't see the humor...I see cheater. What do I make of this when he swears up and down that he is basically very few of one of the good guys that would never cheat. Yet, I know that if he would cheat he would never tell me. He expects me to get over this and to trust him. How? Advice would be great ASAP!

I've heard that a number of times...turns out most of them that say they arent like other guys........ARE! Its hard because you want to believe/trust him, but theres that womens intuition we have that makes us feel something just isnt right. I always tend to go with my gut instinct. Dont let your guard down on this, because IF he is lying, he'll know that he can get away with it again, and again. He'll twist/turn things around to make you think your blowing things way out of proportion. I dont have any advice on what you can do, because the more you dwell on it, the more you might push him away. I dont know if theres a way you can actually find out what happened, but until you do, you just have to not bring it up to him anymore!!