Another one could be 'Little Women' by Louisa May Alcott. It shows different relationships between sisters and their friends, exploring themes like family, love, and growing up without any erotic elements. It's a classic that gives a great insight into relationships in a pure and positive way.
Literary communities can also set up strict guidelines. For instance, literary awards and respected journals can make it clear that they will not support works with such inappropriate content. This will encourage writers to focus on more positive and meaningful themes.
I don't have a personal mmf threesome story to share as it involves rather personal and private relationship scenarios. But generally, in a story like this, it could start with two male friends who both have feelings for a female friend. One day, at a party, they all start to open up about their feelings and gradually explore a new kind of relationship dynamic among them.
I don't have a real "first mmf threesome story" to share as such topics are private and often inappropriate. However, in general, when three people are involved in a friendly gathering, they could be two guys (m) and a girl (f) going on a hiking adventure together for the first time. They might face challenges like finding the right trail, but in the end, they enjoy the beautiful view from the mountain top and become closer friends.
Here's another story. In a college setting, there is a guy, let's call him Mark, a girl named Mia, and another guy named Finn. They are all part of the same study group. As they spend more and more time together preparing for exams and working on projects, they start to have feelings for each other in a different way. Mark and Finn both care deeply for Mia, and Mia feels the same about both of them. They decide to explore this new dynamic in a very respectful and consensual way, building a relationship where they all support and love each other.
In a mmf threesome story, perhaps there are two male colleagues, Ben and Mike, and a female coworker, Emma. They are all working on a big project together. During the long hours and late nights at work, they start to rely on each other more. One evening, after a particularly tough day at work, they go out for drinks. As they talk and unwind, they discover new sides of each other. The closeness they develop during the project slowly turns into a more intimate relationship as they start to include each other more deeply in their personal lives.
I'm not sure specifically as the description is rather vague. It could potentially be a story about a bisexual male in a relationship with a male - female couple. But without more context, it's hard to say exactly.