This piece was originally published on the Blowfish Blog.

So there’s this trope I sometimes see in monogamous relationships. (In particular, I see it in advice columns: it came up in a recent Savage Love column, and I’ve seen it more than once in the Dear Abby/ Ann Landers ouvre.)

It goes like this: "My partner has a friend. The friend's sexual orientation is towards the gender that my partner happens to be. Is it reasonable for me to be jealous? Should I permit this friendship to continue?"

(Or the reverse: "I have a friend. The friend's sexual orientation is towards my gender. Is it reasonable for my partner to be jealous, and to want the friendship to end?")

Okay. In trying to make this generic and gender- neutral, I’m being a little obscure. So let's clear it up and make it specific: "My wife has a new friend from work, a straight man she sometimes goes to basketball games with. Should I be jealous?" Or: "I'm a straight woman who's developing a friendship with a lesbian. My husband is jealous. WTF?" (Both real examples from real advice columns, btw. Dear Abby stupidly advised, "By no means should you permit your wife to attend basketball games with another man"; Dan Savage, much more wisely, suggested that the husband of the woman with the lesbian friend should get a first class ticket for the clue train.)

Now, I'm not going to get too deeply into the obvious. I'm not going to get into the craziness of the idea that any and all friendships will eventually turn sexual if the sexual orientations line up right. I'm not going to get into the fucked-upedness of the notion that people should choose their friends entirely on the basis of gender, for the sole purpose of avoiding possible sexual attraction. I'm not going to get into the absurd paranoia that even the slightest hint of sexual attraction in a friendship will eventually overwhelm it with uncontrollable passion. (Hey, for some of us, having a little attraction for a friend makes a friendship more interesting... even when we have no plans whatsoever to act on the attraction, ever.)

And I'm not going to point out that, according to this theory, gay men could never have gay male friends, and lesbians could never be friends with other lesbians.

I'm not even going to get into the borderline- evil concept that people in relationships have veto power over their partners' friends. This is just R-O-N-G Rong, stupidly and evilly wrong, in all but the most extreme circumstances. ("My partner is making friends with the man who tried to murder me." Okay, you have veto power. Everyone else, shut up. Your partner is a free agent, with the right to make their own damn friends independent of you.)

Here's what I want to say instead:

So what are we bisexuals -- chopped liver?

According to this theory, bisexuals could never, ever have any friends at all. We couldn't be friends with gay men, straight men, straight women, lesbians. And we definitely couldn't be friends with other bisexuals. According to this theory, the fact that we're attracted to both women and men makes us ineligible to be friends with anybody, of any gender, ever.

No, that's not quite true. We could be friends with non-monogamous people, and with single people. But once those single get into monogamous relationships -- blammo. That's the end of that friendship.

I'm not just writing this to point up the stupidity and irrationality of this particular form of jealousy. I'm writing it to point up the stupidity and irrationality of bisexual invisibility.

We used to be a culture that assumed heterosexuality. We still are, to a great extent. But even when we don't assume heterosexuality, we are still, far too often, a culture that assumes monosexuality. We are still a culture that asks, "Is he gay or straight?" We are still a culture that sees a woman dating a man and says, "Wait a minute -- she's straight? I thought she was a lesbian!" (Or a woman dating a woman, vice versa.) We are still a culture that ignores the Kinsey scale, the spectrum of sexual orientation -- and the shifts that many of us make over that spectrum throughout our lives.

And this assumption leads to some truly convoluted errors in logic. I recently wrote about an example of this here in this blog, about how the "Is sexual orientation a choice?" debates almost always ignore bisexuals... since even if bisexuals are born bisexual, we still have some degree of choice about which direction to take our lives in. And the bisexual wars in the lesbian community led to my favorite piece of Alice in Wonderland political logic ever: "The lesbians will decide who is a lesbian."

I can see why people tend to overlook bisexuals. Our existence does poke holes in a lot of conventional wisdoms -- especially when it comes to sorting our society by gender and sexual orientation.

But... well, that's actually my point. The existence of bisexuals pokes holes in the sorting of our society by gender and sexual orientation, pointing up ridiculous contradictions and convoluted logic that would be hilarious if it weren't so annoying.

So maybe we should quit sorting our society by gender and sexual orientation.

And maybe we should start with our friendships. And the friendships of our spouses and partners.

Which are none of our damn business anyway.