False. There is always different than you. Which isn't really the same thing. Say you're a jovial, fun-loving guy. Even if you act alpha as fuck, things like boredom (i.e. failure to maintain mystery), a bad fight, illness on your part, the chattering of her single "friends," or all the above, could easily cause your girl to hamster that your fun-loving disposition makes you a dork, or goofy, or 'immature.' Then she might wonder what it's like to get dicked down by the "strong, silent type." And there will be guys in her life who fit the bill. Say you're that strong, silent type. The aforementioned factors could cause her to hamster that you're a passionless stick-in-the-mud and that what she really needs in her life is some outgoing joke-cracking dude. And there will be guys in her life who fit that bill too.
Same goes for occupation. Maybe you're a red-pilled lawyer or finance wizard or programming guru providing her a high-dollar lifestyle. But she might hamster that broke-ass Mike who knows how to work with his hands is oh so hawt and masculine and "like, why doesn't my so-called man know everything about cars and plumbing??" In which case you can be sure broke-ass Mike won't get the "I have a boyfriend." treatment if he comes calling.
The examples could fill volumes, but I'm sure you see my point. You don't have to be a limp-wrist male feminist or a fat neglectful husband to get cheated on. You really don't even have to be BP. You just have to be in an "exclusive" relationship. Some on TRP are perfectly happy to swallow the blue-pill when it comes to absolving a woman of all responsibility if she can't stay faithful. They assume it must be the man, and not the whore, who is fucking up so all they have to do to not get cheated on is "not fuck up." That's unfortunate, because the truth of the matter is this: her slutting around isn't a cold anthropological calculation of her future offspring's best chances. It's an impulsive wild cock chase, with her feelz and tinglez leading the way. Hypergamy doesn't necessarily work upwards (though she'll ALWAYS convince herself that she's upgrading). That might be the bio-evo ideal, but in practice it often goes laterally or even downhill from any objective standpoint. Trouble is, in the face of her feelz objective reality doesn't mean shit.
My advice? Don't stay up at night worrying about it, but realize that even acting RP can only reduce its probability; you can never totally eliminate it. Have a rapid-release plan and be prepared to deploy it ruthlessly. I know a lot of dudes on here advocate demoting her to plate status, but to me that looks an awful lot like rewarding terrible behavior. She's still getting the sex she craves while you merely withdraw your commitment as "punishment." Hell of a punishment considering if she gave a shit about your commitment, she wouldn't have risked losing it by cheating on you. Men are the gatekeepers of validation as well as commitment. Withdraw both. I suggest going Casper The Indifferent Ghost on her ass and delete her from your life. No matter how relentlessly she tries to get back in, she's only sorry she got caught.