It's hard to define the qualities a man might possess that would make a woman willing to do let him do as he desires with her body. I could vaguely describe them as 'alpha' qualities, but it's more of a 'you know it when you see it' kind of thing.
It does tend to feel clearer when you're married to a cuck. He's a wonderful husband, of course, but he might not be the ideal sexual partner. He might not be the sort of man that absolutely lights you up when you get naked with him.
It's more likely he's the sort of man that inspires you to crawl onto his face and ride his tongue to multiple orgasms while you deny his dick.
The other kind of man, though? The kind that you'll let do as he pleases with your body? You can feel it when you meet that kind of man. You can feel it the moment he puts his hands on you, the moment his lips find yours for a kiss. You can feel it between your legs. You can feel it throughout your body. It's like the reptilian part of your brain is suddenly screaming at you and demanding that you do whatever this man wants because he's going to make you feel so good.
What sort of things would a hotwife be willing to let a man like that do to her? Well, I can't say for sure. It really does come down to the man, to the way he makes her feel. Here are some of the pleasures she might grant him (that she wouldn't grant you):
Cum On Her Body and/or Face - She wouldn't dream of letting her cuck cum on her face, but if a man like her bull wanted to mark her with his load, she might let him. She might, in fact, enjoy it. She might also do it because she knows it will arouse her cuck to hear that she let someone else cum on her body.
Anal Sex - Some men really want to fuck a woman in the ass. If his cock's not too big, she might let him do so because she wants to make him feel good, because he makes her feel so fucking good.
Hard/Rough Doggystyle - Doggystyle isn't all that much fun with a cuck. It is, however, fun to get fucked hard from behind by a man that exudes confidence and perhaps a touch of dominant energy. After all, getting fucked on your hands and knees is an inherently submissive position, and cucks don't really do domination, do they?
Throat/Face Fucking - Your hotwife isn't going to let you fuck her face, cuckold. She's probably not going to give you her throat, either. She might give it to him, though. She might even find it incredibly hot to let him fuck her mouth like that, to let him use it for his pleasure. She might play with her slick pussy and cum incredibly fucking hard as he uses her mouth.
Dressing for His Pleasure - She probably wears the clothes she knows you enjoy, at least from time to time. She probably doesn't let you dictate exactly how she dresses, though, but she might let him do that and he might go all in and demand that she find something spectacularly slutty to wear for him, something she'd never wear for you.
Personal Grooming for Him - Maybe he wants her to dye her hair. Maybe he wants her pussy shaved. Maybe he wants her nipples or tongue pierced. If he fucks her good enough, your lovely hotwife might be willing to make those changes just to turn him on. She wouldn't do that for you, but you don't fuck like a bull, do you?
There are probably dozens more options, though it can often be as simple as he gets to decide when, where, and how they fuck and you don't get any of those options.
It's kind of hot to think about, right? You kind of like the idea of another man - a superior man, really - being able to do whatever he pleases with your beautiful wife's body while you're restricted to the small pleasures she allows you.