I can provide a couple of reasons as to why both the wife and the husband(by incentivizing his wife) could want to engage with different men even if they are somewhat "inferior" to the husband.
Trying something different - Why do you try different flavors of ice cream when you already have a favorite? Maybe YOU personally cannot understand why someone would do that but there are plenty of people who do. In the sex context this is actually very simple to understand, both men and women sometimes want to find out how it feels to have sex with someone who is different(fat, thin, black, white, asian, big boobs, big ass, muscular, etc.), it's not always an issue of finding the better and the best, sometimes it's about finding variety, even more so in this case where the husband encourages it.
Different traits - Even if the main character is a chad, maybe he is lacking in another area, maybe that one average dude down the street has an average face, average job and average body but he has a huge dick. Maybe chad is good at almost everything but lacks the skill of having a sex marathon. You could argue that chad is the manifestation of success but realistically speaking, there is no one in real life that is successful at everything and even in fiction a character like that would be considered bad storytelling.
Taboo and degradation - It's a big reason why a couple would agree for the wife to sleep with an inferior man, the husband in this case may love to see his petite wife bouncing up and down on a fat nerd, the stereotypical man who doesn't have sexual success, he doesn't need to be abusive towards the couple to somehow be on top of this stupid alpha hierarchy, he can be just like a normal guy personality-wise that had a hard time with women and has let himself go a little. It can be a complex but exciting emotion coming from the fact that you the husband is letting a fat, ugly and virgin man have his way with your cute petite wife and therefore is "wasting her beauty" on a man like him that would never have had any chance with her otherwise. The degradation aspect is not for everyone but even then it doesn't need to be super extreme as letting a homeless dude fuck your wife, there is nuance.
Women are build different - For better or for worse there is the fact that women are built differently than men, the whole strangeness of a situation and mood of a sex scene could make them more excited than just fucking a regular attractive guy every day, especially if she is already the partner of that more attractive guy. There is also the point that women like to get attention, an older woman who already had a couple of kids and has that plump "mom bod" can get super excited about the simple fact that they are getting a lot of attention even though it's not from a guy as chad as her husband.
I don't understand why swinging would be unrealistic to you, it's an old, very real practice and it has adepts around the world. It also isn't some young people fad either since there are quite a number of mature couples who do that. I don't know why you personally think it's unrealistic but it connects to netorase since you are in fact lending your female partner to someone, of course you are also fucking someone's partner but this is beside the point. Even though pure swinging and pure netorase are different things this thread was meant to list games that had this type of content without the influence of Netorare since there isn't a tag for pure netorase and sometimes 'swinging' is the closest tag available at least here.
Netorase doesn't mean masochist, in fact it never did, it's not in the meaning of 寝取らせ and it's not in the meaning of the original verb either, I don't know why people are so eager and quick to label it as something purely masochistic. Masochism is one thing and netorase is another. The word doesn't mean masochism in ero game circles either by the way. You can arrive at your own subjective conclusions if wife-sharing is something masochistic or not but I would firmly say it's not masochistic unless the husband enjoys this kind of stuff. This can be a long and complicated conversation but in short, there are also men who enjoy 'cuckolding' on a power-trip and dominant kind of way, the term for this is 'Stag' and someone who lends his wife can very well fall within a variety of categories since not everyone enjoys being humiliated.
I played Babysitter and honestly it feels like a bait and switch to me, the point where you make a netorase choice of sorts seems to be way into the game, you need to already have played quite a bit and even then it's more like an open relationship. Not wanting to give too much spoilers, a girl basically asks about relationships and you can answer that it's better to keep options open and have fun with other people. If you choose to be steady with her I don't think you can willingly lend her in the middle of your relationship, which is a bummer. I have to say though, I didn't play the open relationship route in this game because I thought the other guys are too asshole-ish and the game itself was very bland on the fetish, like something being added just as a flavor, I can be wrong about some things though. I was aware of the new game and I'm happy to read that it has a bigger potential for these fetishes.
