I've read several BLs where people always comment on why they don't show more bisexual characters? This chapter kind of answers that. It's not that everyone is like that, but in his case, being bisexual makes it "easier" to be with a woman than to face criticism for being with a man. If a gay man is only interested in a man, as a couple they both face challenges together. In the case of a couple where one person is bisexual and the other is gay, only the gay person suffers.
I don't know what to say, I don't have money for therapy so I read yaoi.