The exclusive photoproduction of $e^+e^-$ pairs from nucleons close to the vector meson production threshold ($1.4<\\sqrt s <1.8$ GeV) results from two main processes: the emission of Bethe-Heitler pairs
and the photoproduction of $\\rho^0$- and $\\omega$-mesons decayinginto $e^+e^-$ pairs. The Bethe-Heitler amplitudes are purely electromagnetic and reflect mostly the nucleon magnetic structure.
The $\\gamma \\,N\\rightarrow e^+e^- N$ amplitudes arising from vector meson production and decay
are derived from $\\gamma \\,N\\rightarrow \\rho^0 N$ and $\\gamma\\, N \\rightarrow \\omega N$ amplitudes supplemented by the Vector Meson Dominance
assumption. The vector meson photoproduction amplitudes are calculated using a relativistic and unitary coupled-channel approach to
meson-nucleon scattering. They depend sensitively on the coupling of vector fields to baryon resonances. The $\\gamma\\, N \\rightarrow e^+e^- N$
differential cross sections display interference patterns. The interference of Bethe-Heitler pair production with vector meson $e^+e^-$ decay is quite small in the domain of validity of our model for all angles of the emitted $e^+e^-$ pair.
The interference of $\\rho^0$- and $\\omega$-mesons in the $e^+e^-$ channel can be large. It is constructive for the $\\gamma\\, p \\rightarrow e^+e^- p$ reaction and destructive for the $\\gamma\\, n \\rightarrow e^+e^- n$ reaction. We discuss
the shape and magnitude of the $e^+e^-$ pair spectra produced in the $\\gamma \\,p \\rightarrow e^+e^- p$ and $\\gamma \\,n \\rightarrow e^+e^- n$
reactions as functions of the pair emission angle and of the total center of mass energy $\\sqrt s$.
In the particular kinematics under consideration,
our results suggest that the vector meson contribution can be determined quite accurately from experimental $e^+e^-$ spectra by subtracting the Bethe-Heitler term and neglecting the small
interference of Bethe-Heitler pairs with vector meson $e^+e^-$ decays.
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