Partners 'n Love (1993)

David Grodin has an obsessive-compulsive personality. But he is also just plain obsessed with Maxine Smith, his ex-wife of five years and his business partner. Their small business is Mr & Mrs, a small swimwear company he founded but that only became successful when she became its creative director. They work well together and are best friends, but Max feels that they just could not live together and be married to each other. They learn that because of a legal technicality, their divorce was never executed and thus they are still legally married.