Finding Boyfriend Dirty Boxers

So earlier today I look on the side of my bed and see his boxers lying there on the ground, and I was like when did he leave these? So I picked them up to put in my dirty clothes hamper and I saw the shit stain all over them. Now I know it's common for underwear to contain some type of stain but this was just in my opinion disgusting. Do I tell him about them or just keep it to myself ? (I know I just shared it with you guys)