Ufff, I did it. I was really afraid that he would terminate with me (Daeva once said that e.g. in NY recording someone without the permission is illegal - good that I am not in US). I recorded the last session without my T's knowledge - I knew that it was inappropriate and unethical but I did not record it because I wanted to hear his voice but to have a proof just in case. Today I told my T about it. He took it unexpectedly well. Of course I didn't just say: "T, I recorded the last session, it was wrong". Instead I described in details how I felt before the session and why I did it, he said that he understands why I did it and he's okay with it. Of course he thinks that recording without a knowledge/permission is not okay (I think I said it hundreds times today that it was really wrong) but he's okay with it as I told him the reason. He also said that of course he would prefer if I told him before the session that I'd like to record it but then he realized that then I would not have to record it at all and he said that it was not so bad choice to record the session because probably I wouldn't tell him things which I told without the safety feeling due to the recording. My reason of recording was that I wanted to tell him something which could make him very angry so I was afraid that he would use his power against me and no one would believe me. He actually was surprised that I deleted it because he said that I could use it as a confirmation that he's not like my abusers and even if/when I provoked him last time, he did not hurt me so I could listen to it every time I was doubting in him

I thought about it as well but I decided that my feeling that it was inappropriate was much stronger than the need of keeping the recording...
Actually maybe my T is not so bad...