Ugh, can we please stop with these damaging stereotypes about bi people?
There are plenty of acceptable ways to be bisexual, and while some people might fit the boxes you described, there are lots who don't.
These antiquated views are a large part of why, as a bisexual man, I mostly keep that to myself. Coming out is a big deal with a significant amount of associated emotional stress, doubly so when others try to rationalize how you're not a "real" bisexual ("you've only dated women, how can you be bi!?" or "oh you just like fooling around with dudes, you're not really bi" etc).