Amatorculist A rare but interesting word.. To be pronounced as ay-muh-TOR-kyu-list. In Latin Amator means Lover and cul is a dimunitive suffix
So, this term can be used for someone who is an an insignificant, hypocritical, or lousy lover.. Or rather a pretender of affection.
Alas, If you are interested in the proper word to describe an insignificant love affair, rather than an insignificant lover, it is amourette. This means a trifling and/or ephemeral love affiar.
Trifling means Unimportant / insignificant
Ephemeral means lasting for very short time