Misery Loves Company
If you've been seeing a girl for a few weeks and things are going well, take a look at her friends. If they pretty much all have boyfriends, Great! If they're pretty much all single, WATCH OUT.
Misery Loves Company. And there's no better example than women and their friends. Whether they admit it or not, no woman likes to be single alone, and they sabotage each other by trying to slip in seeds of doubt.
This is one of the reasons why ALL married women try to hook up all their single friends by playing matchmaker whether they like it or not. Cuz they know their friends will try to make her miserable along with them.
Set the friends up with your single buddies.
P.S. To get in good with her friends, all you gotta do is give ONE totally romantic night that she can tell all the details to her friends about, and they'll eat you up thinking you are Prince Charming in disguise.