I would be interested to hear more about the time when you found the old videos but didn't delete them. Did you play them or at least click on the "start" button and then stop them? I'm thinking they wouldn't show up in your "Recent" folder if you hadn't, would they?

Were you just busy, or was your attention on something you were trying to get done, or what? Did it cross your mind that those videos were really something didn't need to keep around now that you're living with your girlfriend?

You can be honest with us here. I hope that you will be.

I know how it is with now cleaning stuff off the computer. I haven't done a really thorough cleaning of my email inbox since 2010.

"Former relationship" stuff used to exist only in a more concrete form, like a videotape or hard copy photographs or letters. I think it would have come to mind more readily then that you needed to get rid of it, because if you hadn't, you would have had to make a conscious decision to hide it from your girlfriend.

Stuff on our computers may be completely comparable to those letters and photographs, but it just hangs around invisibly, and it's easy to forget that it's there.

Maybe you need to have a talk with your girlfriend eventually about how the two of you will handle any incoming communications from exes and if you will keep any mementoes from exes. I wouldn't care if my boyfriend had things like prom photos of him with his highschool sweetheart, but that doesn't mean everyone would feel that way.

It sounds like you haven't had that conversation, and that you may not be on the same page. (For example, your responding to the SnapChat message, and your girlfriend not liking it. She may not like your using that app, period.)

I'm a writing person, so I'd suggest writing her a sincere letter of apology. If you're not a writing person, you could say the same things in a conversation. That might be the time to have the conversation about rules for any material involving exes and any communications from exes.

I like the other poster's idea about cleaning up your computer and phone and any other personal electronic devices. I think that would show contrition on your part and would show that you are making a genuine effort to be considerate of your girlfriend.