The swearing is totally fine!!! But there's certain situations people wouldn't go all for it, such as at work to a customer (like Julie at the bookstore) or just meeting a guy as you pick up your paycheck (unless Shelia's upfront like that, then by all means go for it!). Your characters are very raw which is fantastic! I would love to read more of opening scenes like "Scene opens as Ben takes a walk down _______ as the autumn leaves fall." so I can get a feel for the setting and why they may feel worse or better that day.
There aren't any specific scenes that are unorganic, it's just a few lines here and there that seem off. Here's one I just pulled from the top: [BEN: As if you weren't a fucking whore before. I should have taken that Job position, just to see that fucking face of your shows an emotion other than horny...you know you're fucking lucky]. So when I read this out loud, it sounds strange, and not something I'd hear someone say. Novels are full of conversations that don't sound right out loud, which is why books being made into movies need screenplays. But in your case as a screenwriter, it's best to read your sentences out loud and see if they feel right.
I hope this helps and I can't wait to read more!