"I am truly sorry for the mistakes I have made and for the pain I've caused my family," he tells PEOPLE in an exclusive 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."
Sources tell PEOPLE that McDermott, 47, is receiving intense treatment but is allowed to leave to visit his and Spelling's four children – Liam, 6½, Stella, 5½, Hattie, 2, and Finn, 15 months – at their house. "Their priority right now is their children," a source says.
Earlier this month, a friend of Spelling's told PEOPLE that the actress, author and reality star, 40, was "devastated" and "much more heartbroken than anyone realized" about the situation with McDermott.
She is said to be staying strong for her kids, but the friend added: "She could stay with him or not. God only knows."