He can hire a lawyer and file for divorce.
Houston Chronicle
Try to a compromise before you file for divorce.
The Sun
She had hoped for a reconciliation until he decided to file for divorce without even telling her — instead announcing it to a newspaper.
The Sun
Responsible adults do not file for divorce lightly.
Times, Sunday Times
Or wait until he has gone to his 'oh-so much more important job', change the locks and file for divorce?
Times, Sunday Times