Those payments to women were unseemly. That doesn’t mean they were illegal.

https://www.washingtonpost.com/opinions/those-payments-to-mistresses-were-unseemly-that-doesnt-mean-they-were-illegal/2018/08/22/634acdf4-a63b-11e8-8fac-12e98c13528d_story.html
Bradley Smith
Washington Post
August 22, 2018