Do you keep things that your ex's had given to you in the past?

For the most part, yes. Anything I can think of, I've kept, EXCEPT a shoebox of notes from my first girlfriend, and some little boxes she made. I burnt that with a friend because it felt good at the time, but I kind of regretted it a few months later when her and I started talking again. But these days, I don't regret it.