Ulterpartner

Ulterpartner:

An ulterpartner, or protopartner, is a partner of any variety (such as romantic or queerplatonic) that a headmate had before joining their system. This could apply to source partnerships for introjects, or partnerships from exomemories of any headmate.

This does not refer to a current partner present in the headmate's or another system, but a source relationship.

Related Terms
Partner terms with the prefix "exo" often refer to relationships in shared reality.