While I use the terms interchangeably, there is a nuanced and important difference. “Care partner” recognizes the reciprocal nature of relationships in which both people give and receive. It partnership doesn’t have to be based on an equal exchange and it works regardless of whether one person has cognitive illness.
People who prefer the term care partner recognize that there may come a time when the term caregiver better describes the relationship, as the two-way exchange becomes more one-way.
Having said that, and saying that I try to use the term preferred by the person I’m speaking to, it can be beneficial to know and use the term caregiver or caregiving. Caregiver and caregiving come up more often than care partner in internet searches, which helps when you’re looking for resources.