a person that you work with
colleague
the person you are engaged to be married to
fiancé, fiancée
a friend from school
classmate
look at each other romantically
their eyes meet
your boyfriend, girlfriend, husban or wife
partner
a person that you used to have a relationship with (colloquial)
ex
two people in a romantic relationship
couple
a person that you share a flat with
flatmate
a very good friend that you can talk to about anything
close friend or best friend