When does The Ex-Wife return?

The Ex-Wife is a British drama thriller television miniseries based on Jess Ryder's book of the same name. The series stars Céline Buckens, Tom Mison, Janet Montgomery, Jordan Stephens, Clare Foster, Adam Drew and Sam Hoare. The book was adapted to TV by Downton Abbey's Catherine Steadman.
The series follows a young woman, Tasha (Céline Buckens) who is married to middle-aged Jack (Tom Mison) Their marriage appears happy, but Tasha is haunted by Jack's ex-wife, Jen (Janet Montgomery)