How to just stop caring at all ?

I was in a long distance relationship for 2 years like 3 years ago . that guys just ghosted me like cold turkey ,whenever i tried to talk to him he just blocked me . he lives in other country . I had recovered well though he was in back of my mind , recently my best friend ,who was in his id at that time told me once (like a year ago) he had other girl picture edited with him , as his profile picture . I am angry as I didnt get closure after giving that much time .at the time when i was desperate he said he was never serious about me , if he was serious he would have told his family . he said we were just friends who just had fun and just went invisible .I havent seen his picture or texts for 3 years now . but the way he broke up was too dis respectable