Porn on husband's computer

First a little history. Both my husband and I used to have problems with porn. I had a mild addiction, he had a stronger one. This was before we were married, when we were both in high school and the first few semesters of college. I had stopped my addiction when I met him, but his was still going strong. Because of our religious beliefs, we believe that porn is wrong and should have no place in a marriage. So before we were married, he worked really hard to get rid of his porn addiction. As far as I know, he hasn't looked at porn since we have been married (10 months). I ask him about it occasionally, and he always says he hasn't had any problems. Today, I found porn on his computer. Before anyone says I was snooping, he has actually asked me to check unexpectedly because he says the thought of me finding porn on his computer will help to stop him from doing it. What do I do? I'm not angry at him - I'm mostly just sad and scared. I thought this problem was in the past. We are expecting our first baby, and the thought of a porn addiction in our family scares me. I also feel slightly hurt and betrayed, although not too kudu because i understand how hard it is to resist the urge to look at porn and I know it's not anything wrong with me that makes him do it.