"He's walked this journey with me," Hadid said on Tuesday's The Dr. Oz Show. "The patient suffers, but the caretakers suffer too."
Hadid and Foster announced in December that they were splitting after four years of marriage. Hadid was diagnosed with Lyme disease in 2012, shortly after she married the music producer.
"At the end of the day, David never changed. I changed. Unfortunately these are the cards life dealt me. It wasn't a choice, but I'm not the woman I used to be. And I probably never will be again," Hadid said. "My focus, my energy goes to trying to get well. Trying to make a difference. Trying to find a cure for my children. David's life is traveling … loud concerts. I couldn't. I could barely listen to the radio."
The Real Housewives of Beverly Hills star, 52, is mother to Gigi, 20, Bella, 19, and Anwar, 16. Last year, Hadid revealed Bella and Anwar also struggle with Lyme disease.
She said it has been "heartbreaking" seeing her children go through health struggles and have to change life plans, such as Bella, who she said wanted to be a professional horseback rider before giving it up because of the illness. Bella has gone on to have a modeling career alongside sister Gigi.
"As a mommy we are fixers. We want to solve their problems and give them a fair chance and a happy life. At this moment my hands are tied behinds my back because I don't have the answers," said Hadid.
The Dr. Oz Show airs weekdays (check local listings).