Well, here's the test as to whether it was an affair or not...
Were your needs getting met by someone other than your H? ANY needs at all? If they were, this is affair behavior.
Would you have written the things on this chat site and on email if your H had been reading right along side of you? In other words, you weren't open with your H about what you were writing about and to whom you were writing, correct? Anytime you feel the need to hide something from H, this is your clue that it was dangerous to the marriage.
It doesn't really matter if you "intended" to hurt him or not. Any sexual talking outside of the marriage will always be cheating, unless somehow your H is right there next to you and is a part of it.
Does that make sense?
So lets say you and H together went to a chat site and together were chatting to strangers, with the purpose of it turning you both on and then you both turn to each other for sex afterwards. Cheating? No. Just spicing things up.
Now lets say you go by yourself onto the computer and engage total strangers in cyber sex via dirty talking, mutual masterbation, etc, and your H "knows you do this" but is not part of it, you don't include him, he is unaware of the actual words being said etc. Cheating? YES.
Do you see this difference?
Sorry but, until you do, there won't be much for you to work on in your marriage.
I'm not saying he hasn't contributed to your marital problems. I'm just saying that until you see what you've been up to for what it was, you won't be able to mend things with him.
Believe me, I've had to look in that mirror too, so I know how hard it is. But once you really just face it, then you can begin to work through it.