Interesting question, RedDude (referring to your immediately previous post).
Yes, I suspect you may be right, that for the PARTNER of a bi person, rather than for that bi person him/herself, there might be an extra set of anxieties/worries.
Specifically, the partner of a bi person might very well wonder more than otherwise about whether his/her partner might be straying -- whether in fantasy or reality. This because the exclusively straight woman or exclusively gay man might feel less able to relate to or understand the nature of a bisexual's attractions to others. That is, for example, society has over the centuries provided women plenty of context in which to place their anxieties and concern about their male partner's possible infidelities with other women. But there is very little comparable social 'training' for a woman as to what her bisexual male mate may be thinking and/or doing with his attraction to the same sex.
And also, I think I should add a consideration here that MIGHT GET ME SPAMMED WITH HOSTILE RESPONSES (so BE NICE, please). That is, my own opinion, based both on observation of others and on my own internal urges is that the combination of #1, males' natural proclivity for promiscuity, plus #2 the exponentially greater array of opportunity for casual sex with other men vs. with other women (the lore of 'womanizing' notwithstanding) == a greater 'danger' for infidelity in any relationship in which one or both of the partners is a male attracted to other males.
Bottom line, because women (for good reason, historically/culturally/biologically) tend to guard access to their sexuality more zealously, even the most intrepid straight male 'cheater' has a steeper challenge in bedding other men than does a gay or bisexual male, whose same-sex 'targets' are also other men ... other men who are, well, other MEN, who share with them the typical male appetite for and acceptance of quick and 'no fuss' sexual encounters.
If you doubt my point here, just take a look at the respective hookup links on Craigslist. The M4M boards are stuffed to bursting with guys eager to drop their pants and get it on with total strangers, whereas the W4M boards are MUCH thinner, and tend to be crowded with women looking for 'relationships,' NOT casual sex.
So a horny guy, bi or gay, who is in a relationship but who has the urge to stray, can generally get himself laid within an hour or two of surfing the net, whereas a straight guy similarly horny for 'something on the side' has to wade through the natural female 'defenses' and work much harder for what he wants.
Think about it. Surf the net a bit, get laid, move on ... versus all the wine, roses, walks on the beach, third date?/fourth date? rigamarole that is a serious speed bump if not outright barrier to consummating a cheating heart.
Yes, all of the above is subjective opinion on my part, and yes, there are thousands if not millions of examples of straight men cheating. But hey, can anyone deny that it's a helluva lot easier to cheat with another guy than it is to cheat with a woman?
OK, let me have it if you want.