OK. So you have read others' stories about being either a couple with a single bi female unicorn, or being the unicorn oneself.
You want advice about being the partner of a woman who is involved with a couple. You want to get closer to them. What does this mean?
I think we'd need more information. How long has your gf been with her couple? How involved is she (are all 3 deeply in love or is it early NRE days)? Does she see them regularly? How long have you and gf been together? Is this both of your first foray into being poly? Have you socialized with her couple at all yet? Or not even talked to them yet?
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
Mags, F, 60, poly-dating, loving and living with
miss pixi, F, 38
Punk, 41, M
Old Friend, gender fluid
Nick, 35, M (occasional lover)
Hippie, 25 (?)
Dark Wing, 45 (?)