<human>: My girlfriend and I got invited via facebook to a pyjama themed birthday party from a female friend. The birthday friend is a long time not very close friend of mine and has been described by my girlfriend in very kind words before.

At first we both rsvped on facebook that we would go but without consulting each other; me before, her a few days after. The announcement was more than a month before the event so it was not difficult to make arrangements to go.

We did not mentioned it much before I found out my pyjama for the party. She started to seem more and more sceptical about going. Until she told me that she didn't want to go anymore, without asking if I wanted or not. (I thought she even said that I could go without her but now she is denying it)

Now we are one week before the party. I expressed interest in going but not in a definitive way. She is all surprised that when she said that "she" didn't want to go I did not understand she meant "we". She says I only want to go there because there will be half naked women. Truth is there probably be some not so covered people since it will be a pyjama party but there also be a few very close (male) friends of mine that I don't see that often.

She asked me why I would want to go there and I told her that I don't see why I wouldn't want to. She is now encouraging me to "go see my whores" because "that's what I like". She won't tell me not to go but sure is making a scene about it. She is mostly emphasizing the "girls problem".

She will be working until quite late that day, since she has not made any arrangement to be able to go early. If I stay I feel like I'm going to miss out on some fun and go to bed early since she will be tired from her work day. If I go, she sure is going to make me regret it later on.
 
Am I being selfish? Isn't she acting out off jealousy? Why should I not want to go?

Provide a brief overview of the text.
<bot>: My girlfriend will nagg me about going without her to a party where there will be other girls, help me seeing how this is wrong of me.