Genesis 28:9

Esau went to Ishmael and took as his wife , besides the wives he had, Mahalath the daughter of Ishmael , Abraham’s son , the sister of Nebaioth .

so he went to Ishmael and married Mahalath, the sister of Nebaioth and daughter of Ishmael son of Abraham, in addition to the wives he already had.

Then went Esau unto Ishmael, and took unto the wives which he had Mahalath the daughter of Ishmael Abraham's son, the sister of Nebajoth, to be his wife.