The phrase "affirmative duty" means that you have a responsibility to take action or do something, rather than just refraining from doing something. It emphasizes that you are expected to actively fulfill this duty or obligation. Full definition
Would the federal government have its own affirmative duty to provide additional federal funds — which currently make up less than 10 percent of all nationwide funding for K — 12 education? (educationnext.org)
In Quebec, the Animal Health Protection Act (R.S.Q. c. P - 42) includes sections which impose en affirmative duty of care towards animals. (slaw.ca)
An agent who represents only the buyer owes the following affirmative duties to the buyer, the other parties and the other parties» agents involved in a real estate transaction: (oregonrealty.com)