Even if they are, a lot of people "get the ick" about gay men when they have to deal with them close and personally, not even bisexual women are exempt from this.
Men and comphets are wild. The guy cheated on his girlsfriend and he is still panicking about himself and if he is gay rather than the harm to her. Dickhead
Devils advocate here, but depending on the relationship, a seismic shift in my own identity might be more urgent to think thru than how it affects someone I just started dating.
I would argue the issue to be communication. It is his responsibility to communicate his needs with her before violating her boundaries. Its a consent violation at the end of the day.