tl;dr women are constantly looking for a plan B

Went out last night at a concert as a photog; I caught a woman giving me very subtle IOIs while I was waiting for the concert to begin, thought nothing of it, I was here to shoot the concert.

Eventually during the concert she approaches me, we chat for a bit (turns out she is a 25yo single mom); things start getting a bit more flirtatious, adds me on FB (she asked).

Suddenly she drops me saying exactly this: "I'm gonna check if my 'friend' is here if yes you are shit outta luck tonight, if not we can continue this". Her friend was here, some other guy she was flirtatious with.

Basically since she had been waiting alone at the venue for a while I guess she figured she may as well find herself a plan B for the eve in case he didn't show up.

The plan B is real, the hypergamy too. Disposable men.

I am just angry at the time I wasted on this.

EDIT: Forgot to mention an eye-opener about IOIs. She was looking at me on and off but it seemed so subtle, quick glances and neutral; which led me to think she was just looking at things randomly. She actually later told me "couldn't you tell I was checking you out?"; that is when I had a revelation, if this holds true for all women who look at me in pretty much the same way, then I have more opportunities than I thought. Come to think of it that evening I had 3 other fairly attractive women doing exactly the same thing. facepalm