If I were your girlfriend and I knew that a few times a month you were going back and looking over love letters from your ex-girlfriend, I would dump you on the spot.

Sorry, but I wouldn't want to be with someone who was so clearly not over their former relationship.

Keeping the letters is fine, and your girlfriend shouldn't have been surprised or angered by that. It's also fine that you look fondly back on those times with your ex. And maybe looking at those photos and letters once or year or something might be ok. But once a month? Sometimes even more than that? What's up with that?

And that last comment about silly female emotions and telling her to "get over it"? That should've earned you a kick in the nuts.