Sparks (2003)

Jenni and Guy used to be so close, they used to share the same dreams. But, these days, Guy has to go out on her to come home feeling satisfied. Jenni is aware of his infidelities and close to leaving him, until she finally decides to share in his extracarricular pleasures by seducing Guy's main mistress. Something strange happens. Jenni and Guy actually have something in common again and find their marriage re-bonded back together. The old sparks... re-ignited.