I think the cold, emotionless approach to casual heterosexual sex that many young women engage in is partially responsible for the rise in heterosexual males who seek the company of other males, whether hetero-, bi-, or homosexual.
I see a direct correlation between the rise in heterosexual males' dissatisfaction with their opposite-sex hookups and the increase in "bro culture" and "bromance", but taking it even further, in the geometric increase in the number of males willing to accept, and sometimes even actively seek out, companionship with gay men. I see that many or even most of these relationships are usually on the DL, occur late at night, most often at the gay male's home, and are initiated either online or with mobile apps designed specifically for the purpose, and in which both parties are satisfied sexually and emotionally. That satisfaction may be to a minor degree as in a hookup where the straight male doesn't feel like he's going to get kicked out as soon as he orgasms, or even to more intense emotional affairs that might go on for months, or even years.
Because of this, I have come to the opinion, and I stress that's what this is, that there may be good cause to view as different sexual identity and sexual preference. That is to say that while many males who have sex with other males may still consider themselves straight, their actual preference may have migrated to homosexual contact, not only because they find the sex more fulfilling, but because of the mutual enjoyment, they feel generally desirable, and actually, specifically desired.
That said, even in the most casual of hookups, usually for oral sex, the straight male may find it easier to orgasm, zip up, and walk out without fear of having to engage in making excuses for leaving so abruptly, often by prior agreement that nothing but sex will come out of it. Due to the gay male's sexuality, the straight male might view their contact clinically and emotionlessly, whereas with any female with whom he would hookup, he may feel that he runs the risk of becoming attracted.
I base my beliefs here on personal observations of the relationships my fellow gay males have with straight and bisexual guys, and on my own experiences with the same. I have had two 5+ year relationships with self-professed-straight males - one while I served in the US Army with a fellow soldier - and once since.