Would you feel annoyed if your Ex still had feelings for you?

Ok so I totally understand me and my ex were together for 2 years and it ended because well military relationships suck and yeah... any who. So I have a 16 year old sister who is now best friends with my 25 year old ex. Its rather annoying and he was asking her how I was doing and trying to stay in my life through my little sister... Any who tell the loser to move on and I am not sure how you can get it through to him other then flat out telling him to f*** off. And If I were you I would make any interactions that you might have wit him an unpleasant one for him so he can realize that your done with what you USED to have. Basically just be a *****.