Early termination Clause

Please help ! I live in Massachusetts. I have been at the same rental place for past 9 years. My land lord charges $25 / month on something called 60 day addendum (Notice for lease breakage). Recently during my lease renewal, I told my landlord that I might have to vacate due to job change, but I was not sure. The landlord prepared a new lease agreement where he added $500 termination cluase over and above the so called addendum of $25/month I was paying for the last 9 years. When I argured, he says it is upto you. Sign the lease or leave. He is not able to clearly explain the difference between Addendum and termnation fee. He says Addendum is for letting them know in advance that I am vacating and termination fee is termination fee. Is it leagal for him to charge both or fix any fee he likes? I was forced to sign the document as I am not in a position to vacate. Can I take any action against him? Thanks.