I think lots of men keep photos & tokens from previous lives as I suppose lots of women do.
I am only saying this because I came across a shoe box full of old photos of ex girl friends/love interests that my husband had kept, many years back. We had not been together very long.
I was very insecure at the time & felt quite betrayed & convinced myself that he must still have feelings for all these women as he had kept their photos all this time. To be honest, I think I felt threatened by the women in the pictures. (at the time)
At the time he just brushed it off, but I was devastated that he didnt just bin them, or have some ritualistic burning (like I did with all my ex's photos) I still don't think he fully understood how upset I was at the time however.
I think he still has them somewhere, I am just not bothered where and no longer feel threatened by them.
We have been together over 10 years and are completely comfortable with ourselves and our relationship now and I can see it as just a part of his youth that he wants to hang on to. I would of acted completely differently had I found that shoe box more recently. I am certainly a much different person to the one 10 yrs ago.
I also remember watching a stand-up comedien at a comedy cafe joking about his current girlfriend finding his "stash" of XGF pics and the consensus was that this was a very common thing for men to do.
At the moment you have a newborn - you are probably very tired and emotional. A baby places huge strain on any relationship - no matter how strong. You need to avoid making any knee-jerk reactions.
I don't really know what to suggest...
I suppose you need to decide if you can just move on without ever talking to your DH about it or not.