A cushion assembly for a patient interface including an elastomeric support portion and an elastomeric seal-forming structure supported by the elastomeric support portion that is more rigid than the elastomeric seal-forming structure. The elastomeric seal-forming structure includes a first compliant region and a second compliant region separated from the first compliant region by a support region that is more rigid than the first and second compliant regions. The more rigid support region extends to and is anchored by the elastomeric support portion. In addition, for every point in the rigid support region, the inner surface has a negative curvature when the outer surface has a positive curvature and the inner surface has a positive curvature when the outer surface has a negative curvature.