I gave my girlfriend my phone to order food. While searching for a restaurant message, she found an archived chat with my ex.
The messages were from before our relationship, but some were romantic and emotional. She spent hours reading them and then became upset because she felt I had loved my ex more deeply.
I didn't know how to argue with someone about a version of me from the past. We eventually talked it through, but I wish she had never opened those chats. Sometimes old conversations are not secrets; they are simply closed chapters.