My husband's inappropriate content addiction

When we were dating, he told me that one of the things he liked to do, and had been doing for years, was write erotic stories. He even sold some and was a regular contributor for many online erotic literature sites. I figured at the time that since coming back to the Lord that those days were behind him. But off and on through the course of our 2 year (incl. marriage) relationship, I have found evidence of inappropriate contentography, either in hard copy like a magazine, or in stories he had written and hidden on the computer. When I confronted him the first time, it was with a handwritten letter. I'm not very good at speaking sometimes, so writing it down helps me. When he read it, he was very penitent and sorry, and told me I had no need to worry further because he would stop writing. We talked more, hugged, etc. then moved on. Some months later however, I found a stash of magazines and movies in his shop. When I asked about them, he seemed agitated and annoyed that I'd found them, but gave a perfectly believable excuse as to why they were there. (They were a gift from his previous wife while they were together. He forgot they were there but found them while cleaning the shop and kind of re-hid them so that I wouldn't see them and freak out, which I did anyway, until he got rid of them.) After he explained all this, he left the room in a huff, pretty disgusted with me. I even went in after an hour or so to apologize to him for being accusatory (I don't think I brought it up harshly, I'm not that kind of person), but all he did was semi-ignore me and shrug and say, "Well, I can't do anything right I guess" or something to that effect, and went back to what he was doing. He was sullen around me for 2 more days.
The last time I caught him doing something was in the spring. He had moved an old computer out to his shop, he said to be able to listen to music while he worked. There is no internet connection out there, so I didn't worry about it for a while, until he started getting up at 3 a.m. not able to sleep, and going out there for literally HOURS. He would stroll back in around 5 or so, grab some coffee, chat with me and start his day. One day, I got up and stayed up waiting for him to come back in. When he did, we talked about random things, he got distracted and never went back out to his shop, but started work instead. I took that opportunity to go check out what was on his computer, and sure enough, there was an unfinished story on the screen, 2 other new ones, and a really disgusting one that I'd asked him to not finish, that he'd recently put more work into. Well, I left it up on the screen on purpose so that when he came back he'd see that he'd forgotten to hide it, then I confronted him about it. HE WAS MAD. Again, I got the silent treatment and was accused of being a jealous freak. He didn't speak to me for days. Then all of a sudden a switch flipped and he was fine again, and not spending any time in his shop at all. It has not been discussed since.
And now, here I am a year later. Things were going so well this past year, and I was starting to let my guard down, trusting him more with his alone time. But last night I was going through some old files of stuff on the computer, reading through a pamphlet he made of our business, when smack in the middle of it is a snippet of a story! Pretty tame for him, but still, there it was. Scrolling down a bit further, I discovered a clip of what looks like a conversation he had with someone on an online forum. (Sometimes he'll type out responses in Word, then cut and paste it to the site, so that he can spell check, or so that the site won't lock him out if he's making a long post). From what the clip said, it looks like he's been having a conversation with someone about sexual fantasies. And he's been posting stories to this particular site, but I don't know what the site is, he only called it EP. He's a member of so many forums I can't keep track.

I have known about this latest escapade of his for 2 days now and I don't know what to do. Considering the escalating reactions I got from him the last times that I've said something to him, I don't want to bring this up. I'm scared. Why does he keep so many secrets from me? He hides the stories, he's on a mystery forum where, apparently, it's ok to post erotic content. From reading these latest writings, he has fantasies I didn't even know about, and we're pretty open with each other about that stuff. Why didn't he tell ME? Why is he confiding things like this to a complete stranger? How long is this going to go on? How long do I just pray? I feel I can't do any more than that because of his previous reactions to me. He makes me feel like I'm the one with the problem and how dare I go through "his" stuff, and how dare I accuse him of anything improper. He has a bad temper and has displayed it before on unrelated topics. I don't know what he'd do if I brought this up.
I need prayer. And help for me, I guess. Cuz there's no getting through to him right now. He needs to come to some realizations on his own maybe. Or be confronted by someone other than me. I don't know.
Someone please help! (I'm sorry this is long, lots of back story)

Thank you both for your replies, and prayers for me. I know God moves on His own timetable and in His own way, so I may not see the changes in hubby that I want, but I know that God can change ME in ways I probably cannot even imagine. Continued agreement in prayer over this would be greatly appreciated, Romanseight, especially for that peace you were talking about. I am 7 months pregnant, and stress is not a welcome visitor in my life right now!

Those are both great ideas! Yes, hubby is a writer through and through, and I've never discouraged him in it, as he is extremely talented. He has written things other than erotica, such as a children's story, editorials for farming newsletters, even an unpublished novel, though it does have some no-nos in it. He loves to write. It is his outlet. The problem is his mind gets bored with what he is writing sometimes, and so it wanders into bad territory. I will tell him about CreateSpace though, that sounds awesome. I think he would be very encouraged to see his name in print!