The defendant failed to establish, prima facie, that continued enforcement of his maintenance obligation pursuant to a stipulation of settlement incorporated but not merged in the judgment of divorce would create an extreme hardship ( see Domestic Relations Law § 236 [B] [9] [b]; Mahato v Mahato, 16 AD3d 386; cf. Lewis v Lewis, 43 AD3d 462, 463). His remaining contentions are either without merit ( see Costantino v Costantino, 225 AD2d 651) or not properly before this Court ( see Sloboda v Sloboda, 24 AD3d 533).