You can't prevent other people from being attracted to or even hitting on your boyfriend. Attempting to confront them will make you appear insecure, and in some cases will only fuel the flirting/hitting on, as the individual might believe they're getting to you and your relationship.
Likewise, you have no control over how your boyfriend responds to their behavior. He is mature enough to be able to deal with these girls himself, either by ignoring them or telling them outright he is not interested (if they come onto him). He may not even be aware that these girls like him, while you are too aware of it.
However, if he seems to enjoy their attention, spends time with these girls and flirts back, even after you've told him how you feel, you need to decide if you want to be with someone whose need for attention is more important than your feelings.
Get rid of him!
just like you get rid of anyone else... you use a gun
Sounds like he/she doesn't like your boyfriend or is afraid of him. Has your boyfriend ever mistreated the cat? If so, get rid of the boyfriend asap!
Politely tell him that you are committed to the boyfriend that you have, and want to keep it that way.
Just say it's not that you don't like him it's just you don't want a boyfriend right now.
Don't be mean of course! just come up to her and say you don't like her that you only think of 'us' as friends. it'll come to her that there are plenty of fish in the sea! you are probably not the one for her. but remember you can't just get rid of girls like you get rid of pesty insects!
Absolutely Not!!! If he cheated on you once, he'll do it again. Get rid of this loser NOW. There are way too many nice, wholesome boys out there trying to find girls like you, for you to hang onto this guy.
tell her off nicely
Girls dont get those things daily and you should not think you even deserve them daily, but yes you can get rid of that guy.
Break up with him.
Call the police.
you need to get rid of him ASAP , no one needs this type of boyfriend, he just wants sex and not a relationship, so get rid of him, you are too good for someone like this guy!