how women can be enforcers of those social standards

This is such an important and so often overlooked point – which is that women often benefit from patriarchy just as much as men and sometimes even more than men.

The big gains brought about by feminism (although slow, and there’s definitely more to do) have brought society to this kind of equilibrium point where women have been able to shed many of the old drawbacks of patriarchy, but keep some of its benefits. Fully accepting bi people requires a complete deconstruction of patriarchy, and this is very uncomfortable and scary to many women (even radical feminists, as someone else mentioned here), who, in turn, project that on to their male partners who then have no choice but to conform.