Do you think I am right to be worried?

[MRworried]

Hello,
My ex and I have been seperated for about 1 year now and we have a six year old daughter together. When we seperated we decided that we would forgo the lawyer route in favour of working out schedules and things between us since we are still civil to each other, or rather were I should say now.
Forgive the long story but I feel having all the facts are important.
We seperated becasue she said she could not deal with my jealousy. She was aquainted with a man she works with and over a three month period she began spending up to three hours a day online gaming with him at home, then she bagean to go and spend 3 hours each sunday evening with her D and D group of which he was a part. Then she began spending two hours on wed. nights at tai kwan doe of which he was a member. To this day I do not know if they attended these groups as I never followed her or asked around about them.
Not being secure enough to handle the situation I could no longer tolerate it and , undertandably I thought at the time, she decided to move out. We decided that we would share custody and for the first few months it was great, I could see her whenever I wanted. We also decided that since she was living with her, that when my ex started dating again she would inform me as we both agreed that we had the right to know the adults who had access to our daughter. I should point out now that having been abused as a child myself I am very sensitive about the matter, she said she understood this and I thought we were fine.
With the economic slump I found that there were no jobs in my field in my area so I was forced to move about a thousand miles away for work. I called my daughter every day and we had as good a relationship, I felt, as we could, only being able to see each other for a couple weeks every couple of months.
I started sending her things to help us stay in touch, one of these things was a netbook I hoped we could video chat with.
So all seemed as good as it could be until a week ago. My daughter brought her netbook to my house to show me some movies she watches. when she booted it I noticed a chat program was installed, this concerned me as before I sent her the computer I was very carefull to install web filters and the like.
I checked the chat logs and found that my ex has been using my daughters computer to correspond with two different men, one of which was the co worker mentioned before.
I here and now take full responsibilty overstepping the boundries of privacy. I perhaps should not have read these logs, but in doing so I discovered that her and the co worked were indeed lovers, he had a key to her apartment and that my daughter had seen them sleeping together. There was some graphic sexual conversation.
The chat with second man was much more graphic as they had not yet met, but are as we speak spending a four day weekend together while my daughter stays at her grandmothers house. My ex has never mentined either of these men to me and I am sure she would have denied them had I not found the logs.
I was very upset about her leaving graphic text on my daughters computer in an unlocked folder. As you can imagine I was also very upset abut her betrayal of our terms and her attitude now is that I have no right meddle in her affairs and she has basically stopped talking to me. I can still call my daughter whenever I want and pick her up for visits also.
In one of the chats with the new man, this person says that his plans for the night are to "find some sailor mercury porn and j*** off." There were no lol's smiley faces or emoticons to indicate it was a joke. For those of you who don't know, sailor mercury is a 15 year old japanese school girl cartoon, and in my mind, borders on child pornography. Now, this is my question.
I say "borders on" because I don't know if I am being driven by jealousy or if my concern is legtimate. I do not know if this was said jokingly,(although joking about child porn isn't that tastefull ethier) or whether this man has a fetish for young school girls. This man is also a wrestler so I asked my ex to vaccinate my daughter against hepatitis before becomig intimate with him, something she has not yet done and seemed oblivious to the danger.
So am I freaking for nothing? I know I invaded her privacy, but given what I know I am glad I did. I need to know what impartial observers have to say because frankly I am so unsure of whether or not I can trust my feelings or whether I am just trying to sabatoge her relationship.
Thanks in advance for any insights you may have.