How do I get rid of these lingering feelings?

My girlfriend and I broke up a year ago. He left me for a foreign man she just met who was richer and more good-looking than I am. Yes, it has been that long since we broke up but recently when I saw her, I can't help but reminisce all the times we had. Maybe I am still hurt or probably still at the stage of moving on because I still have these feelings lingering. However, I don't want to chase after her. I respect her relationship with that foreign guy even if it is the cause of all these. I just want to get rid of these feelings but how?