Addicted to Love

Addicted to Love is a movie starring Meg Ryan, Matthew Broderick, and Kelly Preston. Maggie's and Sam's former partners are in love; she wants revenge and he wants his lost love back, so they work together to break up the happy...
Good-natured astronomer Sam is devastated when the love of his life leaves him for a suave Frenchman. He therefore does what every other normal dumpee would do — go to New York and set up home in the abandoned building opposite his ex-girlfriend's apartment, wait until she decides to leave her current lover, and then win her back.