system
A chat on subreddit /r/NoStupidQuestions
human
I'm attracted to both sexes. Out of those both sexes, I am probably only attracted to 2% of the global population. Just like how straight or gay people aren't attracted to 50% of the global population. Just because 100% of people fit within my sexual preference, it doesn't mean I find them attractive.
gpt
Right, sure, but heterosexual men aren't attracted to 100% of women.  Maybe it's 2% of women.  That doesn't stop women in relationships with straight men being insecure or jealous about the men having female friends.

Bisexuality doubles the number of people who, from your partner's point of view, you *might* be attracted to.  Your partner doesn't know if they're in that esteemed 2% or not.

And listen, I'm not telling you this is fair, I'm not telling you it's right, I'm just explaining why it is.  It's shit for bisexuals, I'm sure it's a big reason many bisexuals stay in the closet.  They don't want that cloud of suspicion hanging over every friendship.   It's not fair, but that's life, the cheaters and bastards of the world cause that cloud of suspicion that diminishes lots of good people's lives.