This happened when he was 28, so it may be different with older people.
He loves the girlfriend, but he also loves the memories he had with his wife. "My husband of ten years died last January, and it has been awful.
I spent 48 hours in a comatose state and woke up to find out she had died from her injuries.
I fully blamed myself for failing to protect her for years and if I am honest with myself I still do to some degree.
She wouldn't have wanted him to be a miserable person so he slowly came around and is now dating someone new.