well why Guy behaves that way? - Is there something else going in his life - i mean some other problem in job,family? have you tried to analyze that. Also, It is very natural and all girl should expect this - whole movie kind of romance doesn't last long.But that doesn't mean that guy has stoped loving.Expectation of girl is always like when the guy is pursuing her.But in reality as someone above pointed once they get it they tend to fall back as they are secure.Kind relax once you run 10k marathon..hehehe this also goes to girl in the scenario as girl would stop making her fit and beautiful .This is human nature. one more thing is :if he wasn't serious , why did he get engaged with you? If you are sure that he doesn't love you, then you should get out of relationship.Long distance relationship is very hard to handle and if there is no trust .get out! Good luck!:) Don't make immature mistakes in love :D