Special relationship

Yes, these are all terms that can be used to refer to a romantic partner or close friend.

"Significant other" (SO) is a term that is often used to refer to a person's romantic partner, especially when the person does not want to specify whether they are dating, engaged, or married.

"Special person" (SP) is a more general term that can be used to refer to a romantic partner, but it could also be used to describe a close friend or family member.

"My other half" is a term that is often used to describe someone's romantic partner, as it suggests that the two people are closely connected and complement each other.

"Twin Flame" is a term that is sometimes used to describe a person's romantic partner, but it is more specifically used to refer to a spiritual connection that is believed to be stronger and more intense than a typical romantic relationship.

"Counterpart" is a term that can be used to describe someone who is similar to or complements another person in some way, but it is not typically used to refer to a romantic partner. --- Human relations