Schreiver is said to be very keen for his partner, who he has been in a relationship with since 2005, to join him in the hit drama in which he plays the titular character, a fixer for a law firm to the rich and famous, reported Showbizspy.
However, the 44-year-old actress is resisting his wishes so far.
"Naomi's made a point of distancing herself from Liev's career, and this is no different. She doesn't like to mix business with pleasure. Besides that, she knows Liev's show doesn't need her help," a source said.
It has already been commissioned for a second series.
Watts, and 45-year-old Schreiver, who have two sons, Sasha, six, and Samuel, four, together, are believed to have made an agreement with each other to avoid starring together on screen.
"Naomi's not going to budge. She believes working on the show would kill their romance - and she thinks Live will thank her one day for turning him down," the source added.