Im jealous of my bf-ex girlfriend!?

I have a bf of half a year. He's a Filipino and i'm a Malaysian. Recently i found out that he and his ex used to plan to get married but somehow the girl dumped him saying that she has her own direction. His whole hometown knew that they were getting married and some still think that they are getting married sooner or later. They had been together much much longer than i do. They knew each other in high school and had dated for FOUR long years. They still keep in touch as friends though.I am so so jealous with her. Somehow, i feel left out. I've never even met his parents. He did ask me to go to Philippines to visit his family end of this year. I know he loves me but i still can't get over his ex. I feel abnormal. Am i being over sensitive or what?Please HELP!