Hmm, how can I put this.
Firstly, I’m not one of those people who thinks bisexuality isn’t real. Neither am I one of those people who has false stereotypes about bisexuals.
However, I think that sometimes people can stumble for a while as they try an work out how they actually define their relationships. It is not uncommon for example for a young man to identify as bisexual for much of his twenties, often having many girlfriends as they mistake the natural affinity they can often have with women for love, only to later identify as Gay.
When such people say they are bisexual they are being entirely honest. However, it can take them time to properly work through what their real feelings are.