Alexa (1982)

About Alexa King, a free-spirited writer from London, her friend Christine, an ex-concert pianist who now lives in deepest Essex, has two children and loves being pregnant but is otherwise bored and disillusioned and Paul, her husband, a teacher who is stuck in a rut. Answering a letter that is basically a plea for help to regain her sanity, Alexa moves in with her friend for a while but it's not long before an attraction is obvious between her and Paul.