Thank you for your Question,
According to the Islamic law a man is free to marry and does not really need anyone's permission. But ethically It is definitely advised to seek guidance form your parents and you should try to keep them happy as much as possible.
I feel it's it just a matter of communication between you and your parents. At times a third person, that your parents respect and listen to can help you solve the problem. I would suggest you speak to your local Aalim and or an elderly to help you in this regard.
Also, your parents may be reluctant because she is divorced. But you can still explain her situation to your parents and hopefully thier support will follow suit InshaAllah