Bisexual Question

I am a fifty-two year old woman, two grown children living on their own, and have been divorced for five years. A year ago, and this was something new to me, I began having a bisexual friendship with another woman, fifty-eight, divorced, and no children.
I really enjoyed this. It was so refreshingly uninhibited and fun. She has a large and very nice house where we would usually get together, and where I loved spending a good deal of time nude with her.
Things seemed just fine between us, and then she began declaring that she was a lesbian. That was okay with me, but she started to become very demanding and would accept my being nothing less than a committed lesbian, too.
I’ll be honest. I don’t really think of myself as a lesbian, just a female who is having some fun is all and enjoying the ability to do that with my own sex. I don’t feel any burning desire to tear down the “straight world” as she calls it, and install lesbian-kind. So needless to say, after she developed this chip on her shoulder, our relationship cooled considerably and of course I ended it. Since then I have missed my female fun and companionship.
My question is, can a woman who is basically straight just enjoy having a bisexual relationship without making it into “something”? Any opinions on this out there?