"why am I having a negative reaction to the prospect of being considered her FWB? I've had FWB in the past and it was a stress free win-win. What I have never experienced is this kind of dedicated FWB where we are in love, live together, split expenses, share affection and laughs when we have time, have sleepovers and secks periodically... It's very good, but I can't shake the feeling that something is missing. "
I'm confused: are you feeling like something is missing in the relationship, or that the label is not accurately describing some aspect of the relationship? Seems more like the latter but I'm not certain.
In that FWB probably doesn't include love for most people, I can understand why you might be experiencing some dissonance.
"That the idea of "relationships take work" is bullshit outright"
Why is the idea that relationships take work so awful? Acting like an adult, taking responsibility for your own issues (the stuff you generally espouse) takes work, and being willing to put effort (work) into things we value (like a relationship) seems reasonable to me. I don't understand the distinction.