should i be more concerned?

Okay so the father of my daughter is a server, he makes good money doing what he loves, being a total people person. Yesterday he left his bag at home that he normally takes with him to work, well i was looking in there for work shirts for laundry and i saw he left his server book in there well i opened it seeing if he took the order slips out and was gonna throw it away its all ratted up and barely together but when i pulled the order sheets out behibd those were telephone numbers from other girls well when i asked him about it he said other servers keep them because its "funny" and i shouldnt worry. Is this really a thing for all you servers out there? Do you keep them or throw them away? They are all from recent months and he said they were all goid tippers and he also keeps them for good luck?? I cant shake how weird it is because if it were me id laugh and throw them away and somethin just rubs me the wrong way about it.. Should i call bullshit? Or just pick my battles?