Raliced, sometimes I've had former BFs show up in dreams, and I always try to understand what they represent, as opposed to who they actually are. For instance, in one dream that I had off and on for years, there was one former BF that is a graphic artist. He's so creative he's a bit quirky. And I realized that I was suppressing the creative side of me IRL. When I took care of that, the dream went away. It wasn't about the guy himself at all.
Mostly, though I think dreams are nature's way of purging and filing.