why does antony love cleopatra?

There are various answers to this question, but the most likely one is that Cleopatra is very successful at attracting powerful men to love her (Julius Caesar included before his death). Since the play starts with Antony and Cleopatra already a couple, it is hard to know what brings them together in the first place.

Cleopatra is an attractive woman who knows how to charm men.In the first act she nearly uses lies to bring him to her. Antony himself calls her enchanting in act one.