Ex-boyfriend?

so i used to date this guy we dated for like 3 yrs. then split up bc he started datin this gurl i mean we were kinda friends but not best friends weve known each other for years. ok so he would bounce back & forth between us until i finally found me sumone that i really cared about. then he still kept tryin but once i got serious with my boyfriend i told my ex no more. so everynow and then when im sittin around i feel like i might want to call him just to see how hes doin or if i see him around i willmost of the time say hey if hes alone. i just dont know what to do i mean how do u ever get over someone that you lost everything to? if u know what i mean ..