Memberships types with relationship type = 'Spouse of' generate hundreds of rows in membership table

Create a new membership type and set the relationship type to 'Spouse of'. Select a contact with a spouse. Create a membership of this type for the selected contact. CiviCRM will "think" for a long time, then fail. Clicking on the memberships tab when viewing the contact or the spouse shows, in my case, 1500 new membership records for both the contact and the spouse.