When the wife of a cheating writer is gone, he must get her back

This logline needs just a little more.
Perhaps tell us what he must do to get his wife back. (if this is an example logline I don't think I have seen the movie)
Does the writer need to change his ways to win back his wife? Does he need to complete some epic task or perhaps prove his love in some specific way?

Also, you should personalize the beginning of this logline.

"When his wife leaves him, a cheating writer must, (Do this thing) in order to win her back"

Hope this helps