Section 5-311. Certain agreements between husband and wife void

Except as
  provided in section two hundred thirty-six  of  the  domestic  relations
  law,  a  husband  and  wife  cannot  contract  to  alter or dissolve the
  marriage or to relieve either of his or her  liability  to  support  the
  other  in  such  a  manner  that  he  or  she  will  become incapable of
  self-support and therefore is likely  to  become  a  public  charge.  An
  agreement,  heretofore  or  hereafter  made  between a husband and wife,
  shall not be considered a contract to alter  or  dissolve  the  marriage
  unless it contains an express provision requiring the dissolution of the
  marriage or provides for the procurement of grounds of divorce.