The 47-year-old actor is said to have cheated on Spelling, 40, with a woman named Emily Goodhand, 28, reported Us magazine.
The actor voluntarily checked into rehab, according to his representative.
"I am truly sorry for the mistakes I have made and for the pain I've caused my family," McDermott said in a statement.
"I take full responsibility for my actions and have voluntarily checked myself into a treatment center to address some health and personal issues. I am grateful to be getting the help I need so I can become the husband and father my family deserves," he added.
The couple, who has been married for seven years, are parents to Liam, 6, Stella, 5, Hattie, 2, and Finn, 16 months.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →*Subscribe to Business Standard digital and get complimentary access to The New York Times
Smart Quarterly
₹900
3 Months
₹300/Month
SAVE 25%
Smart Essential
₹2,700
1 Year
₹225/Month
SAVE 46%
*Complimentary New York Times access for the 2nd year will be given after 12 months
Super Saver
₹3,900
2 Years
₹162/Month
Subscribe
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors
Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share
Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor
Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements
Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
SAVE 25%