Why are some straight women desiring a lesbian

I am a 45 year old lesbian, recently single after 10 years and fell hard for a female co worker who was flirting with me a lot and always staring at me. We were both lusting after each other for a long time. I finally ask her out, she says she cannot, of course I am shocked and told myself to just forget about her. She continues to say hi to me while she slowly passes by and stares from a distance all the time. Problem is I find her so hot but getting too frustrated. I started to think about other crushes I had when I was younger and many of the women always took the first step in approaching me. These were straight identified women who wanted me, some I slept with and some could only handle a romantic friendship, no sex. Why do I keep attracting straight women, I want a relationship with a woman who could imagine having a relationship with another woman. They usually say "I am straight but I am attracted to you" . It is frustrating because they never stay with me that long or come back every time they are not with a man. Is it normal that straight women desire a lesbian?