The music for this aria was not composed by Vivaldi. The originating work is Geminiano Giacomelli's opera Merope (1734), composed before Vivaldi's pasticcio Bajazet. It was a common practice during Vivaldi's time to compile arias from other composers with one own's work for an opera. Vivaldi himself composed the arias for the good characters and mostly used existing arias from other composers for the villains in this opera. "Sposa son disprezzata" is sung by a villain character, Irene. Vivaldi has recently been attributed as the composer of the work, perhaps because Cecilia Bartoli's album "If You Love Me (Se tu m'ami ), 18th-Century Italian Songs") which uses Alessandro Parisotti's 19-century piano version, attributes the work solely to Vivaldi.
Translation in English
Sposa son disprezzata,
L'amo ma egl'è infedel
I am a scorned wife,
I love him, but he is unfaithful,
In the 1880s adaptation by Alessandro Parisotti, the second stanza is left out. This adaption is the most widely heard, popularized by mezzo-soprano Cecilia Bartoli in the aforementioned album If You Love Me (Se tu m'ami).