6 Answers

They are both to blame, if your boyfriend can let this go on right in front of your eyes, tells me he is in on it.If you and your partner remain together, don't be in her company.

"A boy makes his girl jealous of other women.  A gentleman makes other women jealous of his girl."                           ~~  author unknown

Really only 2  things to do, sit your friend down and have a serious talk , or find a new best friend

Girls will be Girls!!:-(..my so called best friend when i was at school used to flirt with everyones boyfriends!..I soon learnt that she had the problem,not me!...I think some girls  and boys are either very insecure and act badly...others want to hurt..and some just want to show you that they can get any man they want...My first thought would be to keep her away from him..but I think you should talk to your boyfriend re your concerns and he will be protective of you if he`s in for the long haul!!...nOW OLDER AND WISER..YAWN!!:-)..I`d question whether you want to hang out with the so called friend..she sounds self centred and I wouldn`t want to be looking over my shoulder all the time she`s around..A TRUE friend would be happy for you!!..GOOD LUCK..NOT EASY..Love Millie xx

This person is certainly not any sort of friend if she is behaving like that with no regard to your feelings, and as for your boyfriend , he is no better if he is allowing this to happen

Ask her openly " Are you flirting with my boyfriend, cause it sure seems that you are"? Also look at how your boyfriend reacts, maybe he is encouraging her because he is flattered.