not sure if i agree with the others or not. I agree you need some time out, but dont burn your bridges. He's been asking for sex...but did he do the deed?
And involving the internet doesnt make it any worse than going up to girls in a bar in my book...in fact it makes it less bad....maybe if it was all just talk? I mean, maybe he wouldnt have really dared to do anything? People can be who they want in an email...but it really depends on if he's been meeting the girls.
Take time out, talk to him....maybe he needs a big think about exactly what he's doing!!! Perhaps it's just been an online game. A game that isnt acceptable but that isnt quite full sex...
Men can be fools. They take a long time to grow up sometimes...a long to time realise what they really want..
I'm not saying to forgive him, or to dump him, just to take your time. This is horrid. Dont react suddenly. Go stay with family for a while.
Good luck