<human>: So, backstory. My boyfriend and I are from City A. We went long distance for college and two years ago, my boyfriend and I ended the LD by moving in together in City B. As we were looking into apartments my sister asked if we would get a 2BR and let her live with us because she wanted to leave City A. We agreed. About six months later my boyfriend moved back to City A for financial and education reasons and my sister and I continued living together. 

Our renewed lease ends in June. I am graduating in December and moving back to City A. My sister wants to move in with her boyfriend. I asked if they could do what I did for her - rent a 2 bedroom and let me stay with them. She turned me down. After discussing options with my sister, we agreed to move apart. I would live in student housing for the last semester (about 3x as expensive as splitting an apartment with then) and she would move in with her boyfriend. She agreed I could live with them in the gap in between our lease ending and my new one starting which is 1.5 months.

I am visiting City A this weekend and yesterday she texted me to let me know she no longer will let me live with them in the gap. Not really sure what I will do now. I'm not working atm and I don't have classes this summer so I am considering living with my boyfriend (in his parents house) the entire summer. That way I could get a job in City A for the whole summer instead of going back and forth. 

If I do this, I don't want to pay rent for the 2 months I will be staying with my boyfriend. I'm sure legally I am obligated but she has effectively blocked me from being able to live there. Emotionally I don't want to pay, that is. Is there any way I could approach this with her? What could she do if I just didn't pay? I am pretty done with her at this point so I don't care about the emotional fallout.

Am I unreasonable for being mad?

Give me the gist of the text in a nutshell
<bot>: My sister is making my life difficult, do I have an option for a petty move or should I just let it go?