diff --git a/mautrix_telegram/db.py b/mautrix_telegram/db.py
index 4f48412c..7446c3de 100644
--- a/mautrix_telegram/db.py
+++ b/mautrix_telegram/db.py
@@ -74,8 +74,8 @@ class User(Base):
     saved_contacts = Column(Integer, default=0)
     contacts = relationship("Contact", uselist=True,
                             cascade="save-update, merge, delete, delete-orphan")
-    portals = relationship("Portal", secondary="user_portal", single_parent=True,
-                           cascade="save-update, merge, delete, delete-orphan")
+    portals = relationship("Portal", secondary="user_portal",
+                           cascade="save-update, merge, delete")
 
 
 class Contact(Base):