The Repo Men actor is said to have sought the comfort of friends and family since the couple separated in January, especially since rumours emerged of a romance between Miller and Robin Hood star Joe Armstrong.
A source close to Law's family told the Daily Mail: "Clearly things aren't particularly rosy in Jude’s personal life. All I can say is that he's gone through a rough time. These things are hard - it's awful. The good thing is that he's busy. He'll keep on working."
When asked if the 38-year-old, who split with Miller in 2006 following his affair with a nanny, had done anything to jeopardise their rekindled relationship, the source added: "No, that wouldn't be fair at all. He's shocked by this."
Another family friend told the publication: "All that Jude is concerned about now are his children."