add another field on Profile Type field

Currently on the profile field there are Single and Couple. I want to add another field on the Profile Type field. How do I go about it?

I'm not sure how to edit that field, since it's a special item. You can, however, replicate its functionality.

To do this, you can add a new item to the field and edit its settings appropriately. After editing the system name, caption name and description, you must select the item type to be a selector, and switch to the advanced section of the item. There, you can enter values to be displayed for users to select.