Adult friend
In a relationship between a boy and a boylover, the boylover is called an adult friend. The term carries no sexual connotation.
This term is subject to the same ambiguity that lies around the term young friend, in that the term is used to describe a variety of different relationships, ranging from passing familiarity to strong companionship. Some that consider themselves adult friends feel a desire to actively benefit the boy, while others feel no more obligation to a young friend than to any other friend.
Many boylovers continue to consider themselves a person's adult friend long after he is no longer a boy. Conversely, a boylover is still called an adult friend even if he has not attained the age of majority where he lives.
The term "adult friend" evolved as a play on the terms boyfriend and girlfriend and is usually abbreviated as AF in writing.