On Tuesday, "The Real Housewives of Beverly Hills" stars Yolanda and David Foster announced they were divorcing after four years of marriage and nine years as a couple. Their decision to divorce seemed like a mutual agreement as the couple released a joint statement. They reportedly started to drift apart in 2012 when Yolanda was diagnosed with Lyme disease and, as it turns out, this had a major impact on their decision.

"Things really changed in their relationship as Yolanda got sick, and then when her health worsened," a source told People. "David travels all the time and they simply weren't spending any time together. They just grew apart and the intense stress over her health and the disease was very hard on their marriage."

"She just felt he wasn't there for [her] when she needed him most and he felt the same," another source told Us Weekly. "It's so sad, but the illness really did come between them."

Yolanda, 51, has three children from her first marriage to Mohamed Hadid: Gigi, 20, Bella, 19, and Anwar, 16. Back in October, while at the Global Lyme Alliance inaugural gala, Yolanda revealed that two of her children have also been quietly battling the chronic disease, as HNGN previously reported.

"When my two youngest children, Bella and Anwar, were diagnosed with chronic Lyme disease in early 2012, watching my babies struggle in silence in order to support me in my journey, struck the deepest core of hopelessness inside me," she said while receiving an award with her children by her side. "This disease has brought me to my knees. Many nights I wish to die. I pray that I will just wash away into heaven, where there will be no pain. I don't deserve this award. This award is for Anwar and Bella. This is my token and my promise to you that I will not allow you to live a life of pain and suffering. I will walk to the end of the earth to find a cure so that you can live a healthy life that you deserve. No child should suffer in the way that you do."