My ex girlfriend now likes women? I feel in a way betrayed....is that bad?

Before my ex and i got together there was a girl who i was kind of talking to but she was Bi.....but i chose my ex over her....my ex would always be like it would suck if you had chosen her because she would of probably cheated on you with a girl....my ex would be against bi girls saying they follow a trend and would be against the idea of lesbians saying she does not get them....she would also playfully accuse me of being gay....i looked at her FB profile and she identifies as bi and is awlays putting lesbian posts and checking out girls as well....i feel betrayed in a way but i also feel she got some of her own medicine for talking so much chit about bi people and lesbians....is it wrong i feel betrayed in a way?