Bones, where was your "early warning system" when you let her be a friend in the first place?
Oh well, we all make mistakes - me included. Somewhere I ran across an idea I like, about a way to think about our social interactions that's helped me a lot. I tended to be so starved for attention and lonely, that I didn't use any criteria whatsoever about people I let myself get involved with. I would overshare, or be a clam, I just got it all wrong - mostly in doormat mode. I got involved with people I should've stayed far, far away from. This image really got me to think about "organizing" myself in connection with other people in my life.
You, yourself are at the center of your "inner circle". The only people who get into the inner circle are those you know you can trust, who are as protective of you as you are of them, the people who are mutually supportive with you. For me, this is my Ds (although one has only recently been invited in; long story)... my hubs... his brother & SIL... a handful of old friends that I've kept in touch with... hubs' D and her family. Even a few of you people here. This is the circle of people that can tell me I'm an idiot and why, and we can even get mad at each other - make up & get over it - and go on.
That circle is inside another circle - further away from you and less intimate. These are people I do business with and rely on; there is a pretty high level of trust here also. It includes people I see socially on a regular basis - some are family, neighbors, etc.
Next circle out, might be acquaintances... people I see infrequently, don't do much with, or our paths simply don't cross much. They don't know much more than facts about me - they don't know "me", in other words.
Etc. I know, this sounds overly formal and people interactions just aren't always like that. But, because of my confusion over boundaries... and the mis-impression or misunderstanding I had about how we are always supposed to be the "same person" with everyone... I never learned that it was OK for me to be one person to business associates, someone else to my hubs/Ds, someone else yet again with myself... it's like having different wardrobes - my 3 piece menswear tailored suits are for certain situations, my funky artsy hippie stuff for relaxed social events, and I tend to wear my jammies till noon now unless I have an appointment - just because I want to and I CAN. The "real me" shows through all those different roles and wardrobes... and is how I am expressed in functionally different situations.
Each circle is like a boundary and has appropriate levels of trust and sharing, involvement, etc. And of course, I design what those are for each circle. Sometimes, people get bumped from a closer circle, out to the fringes depending on their behavior. Sometimes, they choose to go there themselves - that's fine; it's part of how this all works. Anyway, I thought I'd share the idea because when one is building a "safe" inner circle... this is kinda the concept behind it.