Being a gay man, I can't really say for sure, but I can point to a comment that I learned a lot from. It was from a post on Stuff Queer People Need to Know about Lady Gaga coming out as bi.
Other bi girl dilemmas I have personally encountered in my bisexual life:
1) Getting fired for coming out bi at work.
2) Hearing about bi girlfriends needing to run from their boyfriends or husbands, who were so intimidated by their girlfriends’bi-ness, they threatened to break their teeth.
3) Being called a “traitor” or “full of diseases” right to my face by lesbian women.
4) Having sleezy straight boys hit on me for three-ways–because that’s why I exist, to make sure they get their three-way.
5) Being told I don’t exist or that I’m “politically irrelevant” by the gay community.
6) Being harassed when I show up with a bi t-shirt or bi button by gays and lesbians at a queer pride rally or parade, even though I’ve gone there to support all LGBTQ.
7) Being told that I “have a sickness” by straight people who see my bi t-shirt or bi button on the way to the gay parade/rally/event.
8) Being told that I am just a “part-timer” by lesbian, gay, or queer-identified people, even though I am bisexual 24/7, no matter who I am dating.
9) Being told by right-wing religious people that I am an even bigger threat to society because I “choose” my sexuality.
10) Having people like Tila Tequila, Rikki and Vikki Ikki, Megan Fox, and Lady Gaga represent bisexuality to the public, with no counter-representation from regular bisexuals who just try to make it in this world.