  The millisecond pulsar J1903+0327 is accompanied by an ordinary G-dwarf star
in an unusually wide ($P_{\rm orb} \simeq 95.2$\,days) and eccentric ($e \simeq
0.44$) orbit. The standard model for producing MSPs fails to explain the
orbital characteristics of this extraordinary binary, and alternative binary
models are unable to explain the observables. We present a triple-star model
for producing MSPs in relatively wide eccentric binaries with a normal
(main-sequence) stellar companion. We start from a stable triple system
consisting of a Low-Mass X-ray Binary (LMXB) with an orbital period of at least
1 day, accompanied by a G-dwarf in a wide and possibly eccentric orbit.
Variations in the initial conditions naturally provide a satisfactory
explanation for the unexplained triple component in the eclipsing soft X-ray
transient 4U~2129+47 or the cataclysmic variable EC 19314-5915. The best
explanation for J1903, however, results from the expansion of the orbit of the
LMXB, driven by the mass transfer from the evolving donor star to its neutron
star companion, which causes the triple eventually to becomes dynamically
unstable. Using numerical computations we show that, depending on the precise
system configuration at the moment the triple becomes dynamically unstable, the
ejection of each of the three components is possible. If the donor star of the
LMXB is ejected, a system resembling J1903, will result. If the neutron star is
ejected, a single MSP results. This model therefore also provides a
straightforward mechanism for forming single MSP in the Galactic disk. We
conclude that the Galaxy contains some 30--300 binaries with characteristics
similar to J1903, and about an order of magnitude fewer single millisecond
pulsars produced with the proposed triple scenario.
