As such, FWBs alleviate many of the risks inherent in more casual hookups, such as ending up with a bad/inattentive/inadequate lover, a crazy person, or slutty reputation.
But FWBs are not quite romantic either—they lack the explicit commitment to being a couple and building a future together, and also the expectation of sexual monogamy inherent in most serious relationships.
In that sense, this analysis is presented in a selfish or morally-relativistic/solipsistic frame that focuses the issue entirely on the desires of the FWBs and ignores the larger social context.
What research has been done to explore effects on the whole (contemporaneous) social milieu of the FWB, and effects on their social and romantic relationships going forward?
It seems more what you are touching on is there could be jealousy issues or mutual friends may pass judgement, and guess what, that happens in every social group regardless of whom has slept with whom. Because they are decent, hardworking, responsible people whom I value and respect.
Part of becoming an adult is not worrying about what your friends think and finding friends that love you for who you are with all of your baggage, instead of constantly judging you. I have remained friends with several of my past boyfriends. We are all in our 50's and 60's now (and yes, I am married and these romances turned friends go back years before I met my current husband and I don't hide them from my husband).
Or one of you started a serious, monogamous relationship with someone else.
Not knowing if I am shaking the hand of one of her former lovers makes me feel like a damn fool sometimes.
Unfortunately, that has also caused me to view her in a less favorable light.
Many have observed that these two other sets of relationships are what really suffer.
Excluding them from the present discussion encourages the FWBs to focus on their own "fun" and ignore the other interests at stake, many of which hold the potential to harm the future romantic relationships and friendships each of the FWBs both individually and together.