DuracellEnergizer said:

Everytime Guy Pearce went back in time to save his girlfriend, his past version was nowhere to be found.

LoL... you need to rewatch the movie. He only went back in time to save her once... and he purposely came a lot earlier to avoid his past self. He quickly takes his girlfriend out of the park and tells her "I'm going to come over later and be upset that you didn't meet me. But just remember that I love you..." etc etc etc.

So yeah, they totally address it.