Yes, it's taking me some time to watch it (sahm).
I'm at week 3 were she's saying she can't say "no" to friends who want more than friendship with her, whether sexual or romantic. This, as you said, is common to all people with some insecurity issues. It's almost like she can't say no because she doesn't want to be alone.
Which brings to mind earlier, where she's talking to her friend in the park and saying in the last year she's been and alone and no one's been there for her but she's always there for them. She should be working on this issue it seems to me.
UPDATE: finished that episode with some buffering issues. yawn.
Not really much on poly at all. She's just an individual who can't say no to others and needs to figure out what she wants. Setting up boundaries for herself may work, but I doubt over time she'll follow through with them.