That's a primal taboo: don't go out with your friend's boyfriend or ex-boyfriend. As previously described on this blog, I was a victim of that violation: a frienemy dated and slept with a guy I had been seeing; he and I hadn't even broken up! I was surprised when I told the story to a friend, who passed it by her 30-year-old daughter. The daughter said that if the relationship is over, the guy is fair game. Maybe so, but you will definitely lose that female friend, and as we all know, female friendships usually outlive boyfriends.
Here's a subset of that kind of behavior in that it too prizes boyfriends over female friends, though it's nowhere near as hurtful. I have a friend who got separated around the same time I did. At the beginning, when we were both shell shocked and needed an empathetic ear, we spent a fair amount of time together. But I soon realized that this woman requires a boyfriend at all times. Not to have one, for her, would be like going without food. It's her sustenance. Her pattern is to go on match.com, meet four or five guys, and within a week or so get deeply involved with one of them. During the involvement she might drop me an email about how great her new bf is, but otherwise I wouldn't hear from her. Eventually though, whether after four months or a year, the bf would dump her and she'd be broken-hearted. Then, just like that mole arcade game -- where the irrepressible mole keeps popping up no matter how many times you pound it down -- she would immediately reappear on match and begin the whole process over again.
This pattern has been going on for the past five years, leaving her with periodic two- or three-week gaps between boyfriends. It is during these breaks that she resurfaces in my life and is suddenly interested in my company. The instant her next relationship sparks -- and that never takes long -- she disappears again. The only exceptions are when the boyfriend-du-jour is out of town, in which case she will occasionally call and offer to get together.
This isn't frienemy behavior -- in fact, she is not the type to date a friend's boyfriend -- but it is fair-weather-friend behavior, and she makes her priorities clear. Consequently, I made a mental note to demote her from former friend to current acquaintance whom I'd see out of boredom and only if convenient. Oddly, though she operated that way herself, she apparently had a different view of our relationship. So when the last boyfriend kicked her out of the apartment they shared and she found herself temporarily homeless, she called to ask if she could bunk with me for a while. I was amazed that I was the first person she called, because if I found myself in similar straits, I would have called at least eight other female friends before I'd think to call her. Needless to say, she was angry when I let her stay for a night but declined to house her for longer. What she didn't understand is that I felt no loyalty to her because she had done nothing to engender it.
Moral of the story: Don't take your female friends for granted. Girlfriend relationships need tending too, just like relationships with guys. Especially because in the end, it's your girlfriends whom you will turn to.