@Merilirem
The point for those who enjoy it, as I've asked this question you just did before in the circles I run, is that they're imagining themselves as the male victim (husband/boyfriend/brother/son), and they're typically the sort who get off on being degraded. It's kind of the point of cuckold porn. Apparently you can have it without, depending on taste, but it seems by and large it's that someone who you'd normally think less of is a more aggressive and better sexual match for your emotionally-close woman whose support and attention you rely on. Usually by the end of these situations the woman is either openly or quietly completely enthralled by the dumb, ugly, vicious villain with a huge dick, bigger muscles, and less likely to treat her like she's made of porcelain - for most women who like the same porn, the position they tend to try and feel out is obvious (there's also cuckqueaning for those looking for a similar role as the previously mentioned degraded male). For that to be the case, the male victim has to be relatively puny and not willing to be experimental or assertive. Thus it becomes circular, and oddly enough complete.
Like, you're not supposed to think of yourself as the guy barging in, that asshole Chad who's either super ugly or the guy's boss. You're not supposed to respect him at all. He's just the "assertive element" that turns the tables on the aforementioned puny, submissive guy.
... But basically, fuck NTR.