The British actress secretly separated from him several months ago, but they remain on good terms, reported People magazine.
"They are still friendly and spend time together in LA when Kate is there. There has been no drama. It's just not Kate's style. They have both had complicated schedules and have grown apart," a source said.
A spokesperson for the pair, who have both regularly been photographed without their wedding rings in recent months, has yet to comment on reports they are no longer together.
Another source said, "[They] have a genuine connection based on a friendship."
Wiseman and Beckinsale, 42, are apparently determined to protect her 16-year-old daughter, Lily, with former partner Michael Sheen.
The source added, "Kate is not dating and only focused on her daughter and work. [Len's] primary concern in all of this is Lily. He loves his stepdaughter and is there for her.