<human>: Can you give me the gist of the text in a nutshell?

I asked her out a while back but I figured out that she had a boyfriend... Now because I talked to her one of my friends saw her at a meeting and they got along well. They both hang out a lot and the girl I like now has pretty much joined my friend group. I tried to stick around the group and hang out too but every time I do and I see this girl I think why is she even hanging out with us? We all have known each other for a while and she's a year under us... The only reason is that she clicks well with one girl in my friend group and basically gets invited around everywhere now...

I feel like if I didn't go on that little date in the first place this could have all been avoided and they never would have met... I can't help but feel that she made her way into my friend group without my consent when I'm the first person she has met out of the group... She had a boyfriend and I wanted to cut all ties with her.

And that's exactly what I planned to do but look at where I am now. This girl is pretty much set in the center of my friend group and I am the cause of it. I don't want to talk to her, I don't know this girl, she hasn't been around this group from the start, why should she get a special ticket in?

I think the real thing that pisses me off is that it's not fair. She didn't want to date me and I was okay with that so I then made the choice of not wanting to be her friend. But then she some how gets into my group of friends and now I'm put into this position where I should befriend her.
<bot>: Met girl, went on date, she has a boyfriend, cut ties, she somehow found a way into my friend group, feels like she is replacing me, what do?