Am I being fair to my husband?

I've been married for about a year, and we've been together for 3. Recently found out that he had been dating around/still involved with an ex (who he has no contact with now)/kept his online dating profiles active for the first few months of our relationship. He said that this all happened before he was serious about me (and it WAS before he told me he loved me, but I didn't think he was dating anyone else), and before he knew what I meant to him. Meanwhile, this was going when I WAS already very serious about him, so I feel like I was cheated on. When I told him this, he apologized to me, felt terrible that I felt hurt, etc., but he thinks I'm over reacting.

I have no doubt that he's committed to me now and has been for a long time, but I'm really mad about this because I thought he was exclusive to me THEN. I love him and want to move on from this, but how do I look at him in the same way? Is there a healthier way I can look at this situation? Does this even count as cheating?

Am I being fair, or do I just need to get over it?