Why would my now long distance ex boyfriend have a problem with me saving messages on Snapchat between me and him?

i did it because i forget sometimes which i told him that, like he didn’t have a problem with it before, but when he broke up with me it became a problem? he's like i forget sometimes too, but you don't see me saving them.
Why would my now long distance ex boyfriend have a problem with me saving messages on Snapchat between me and him?
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