I would say they are jealous. But even so, you and your girlfriend remain the "tease de jour" because you have put up with it for this long.
Why should they change, now?
I wonder why you have not ended these "friendships" long before this.
Your girlfriend should have never put up with YOUR behavior of not confronting these ya-hoos.
.
@PUNKEY,
At aged 18 I had quite a few friends I needed to cut loose but hadn't done so yet. However, after the first year of college I learned a lot and was far more selective thereafter.
@jrice94,
ask your friends why they hates her. i think i AM SURE one of them likes your gf ..