It's been a difficult week for Dr. Paul Nassif ... because one day before he filed for divorce from Adrienne Maloof, his father passed away.
Nassif just released an emotional statement to TMZ ... saying, "Adrienne and I have tried very hard to make our marriage work, but this is the best course for both of us."
"This is a difficult time for our family and my prime focus is to ensure our boys are well and happy."
He continues ... "In addition, sadly I just lost my father yesterday -- a man who taught me how to be a man. I deeply appreciate the outpouring of support from family, friends and patients. We will get through this."
Maloof was expected to file her own set of divorce papers earlier today at the same time as Paul ... but backed out at the last minute. It's possible she changed her plans out of respect for the Nassif family.