Why is she angry at me if she has a boyfriend?

I hung out with this girl once and we had a really good time--never had that good a time with a girl before. However, she had a boyfriend. I thought maybe she was still looking since her boyfriend lives out of state and is quite a bit older than her (and I'm her age). We made plans to meet again.

However, a few hours before we were supposed to meet, she canceled on me because her boyfriend surprised her by flying in and visiting. She was extremely apologetic. I didn't reply. The next weekend she apologized again and tried to hang out with me, but I don't want to be anyone's second option, so I made an excuse.

A few weeks after that, she wanted to get dinner with me, but I declined that, also.

Now she's mad at me. She hasn't replied to my last text. I don't want to meet up with her anymore because of the boyfriend situation, but now it's gotten to the point where she's ignoring my texts, too. It's basically just as well because we shouldn't be meeting up, but why would she be mad at me? I mean, she has her boyfriend anyway.

Why is she angry at me if she has a boyfriend?
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