I see a parallel between bisexual erasure and the kinds of dismissals dished out at me when I say I have feelings for multiple people.
Bisexual erasure refers to the belief that bisexuals are either closeted gays, or an intermediary step toward homosexuality. A both coarser and subtler subvariant of erasure is the idea that bisexuals are simply slutty, needy, attention-whorish, and therefore unable to have committed relationships.
What I`ve noticed when I talk to monogamists is that they use the word 'relationship' to mean a monogamous
relationship. Therefore, wanting to have multiple partners is tantamount to not wanting a relationship (or, anything 'serious' anyway), and simply an intermediary step doomed to be left behind once you find real love. Oh, you will see when it happens.
I`ve recently got this from my best friend, who`s gay, super-hyper sexually active, and yet an ideological monogamist. Have you encountered this mono-monopoly over the word 'relationship' often? How annoying is it?