I could really use some opinions on this one.?

I think there is something mentally wrong with my husband. I have been married for about a year and a half and our life has been going down hill, big time. I just got back from out of town, i was only gone for a week, and when i came back i noticed he was looking at nude pictures. of course he lied about it and said that the computer only registered the bad stuff. and, i'm mad about that because I'm not getting any. but the funny thing is, he was also looking for cartoon nudity. I know he likes to watch cartoons, but now it is getting really strange. He was looking at pictures of naked cartoons for a good half and hour. and stayed up til 4 am doing this. when i am at home, he is in bed by 10 or 11. why would he stay up so late when i am not here, looking at that garbage? Is that similar to kiddie ? I know it's not kids, but is it similar? is he looking at that more to hide what he really wants to look at? kind of to make up for it. he lies like sh**, so asking him does no good at all. I could really use some advise on this one. Is this really as weird and demented as I think it is? I know he was using it as a turn on because he also was looking at real women too. and why is it that when im not in town he has the energy to take care of himself, but when i am in town, he is not in the mood?