Pyro (1964)

Set in Spain, a married American architect (Barry Sullivan) begins an affair with a beautiful but psychotic woman (Martha Hyer). When he refuses to divorce his wife to marry her, she sets fire to his house killing his wife (Sherry Moreland) and daughter (Pilarin Gomez) and disfiguring him because of fourth degree burns. He survives with one thought in mind ..... revenge. Directed by Julio Coll, this is essentially a Spanish film written and produced by an American (Sidney Pink) and with two American actors in the leads. The crew and remainder of the cast are Spanish. It's a low budget exploitation movie that begins with an adulterous affair that turns into a horror movie after the fire sequence. Before he's disfigured in the fire, it's very difficult to have any sympathy for Sullivan's character. He knows he's hurting his family but he continues the illicit affair regardless. The movie gives a brief bit of background about Hyer's past that helps explain her psychosis. The film may be obvious and formulaic but it accomplishes what it sets out to do. With Fernando Hilbeck and Soledad Miranda.