Internalized biphobia (Mild spoilers for House of Cards up to S3 E1/2)

Does anyone else have internalized biphobia to the point where they have trouble believing other people are bi, especially in media?

Case in point: I'm a huge House of Cards fan and started watching the new season today. Frank, the main character, has been shown to have sex with men and women, but I never believed he was truly bi but gay. I rationalized it by the sex he was having a reporter was solely about manipulation (he says something to this effect, but I was convinced he didn't enjoy it all and was just doing what he had to), and that his wife was just his very trusted beard. No matter what evidence was presented (including his wife having an abortion with what was implied his baby), I rationalized it as him being gay and willing to do whatever needed. It wasn't until the first (or second; I can't remember) episode of the new season where it shows him and his wife having sex that I finally started to believe he was actually bi. I guess I'm just really not used to seeing bi characters in media. Does anyone ever feel like this?

(Also, I haven't gotten beyond S3E2 so please no spoilers!)