No Way Out (1987) on Netflix

Commander Tom Farrell of the US Navy is hired to work for Secretary of Defense David Brice after being introduced by Scott Pritchard, Brice's General Counsel and Farrell's former college mate. At that meeting at a ball, Tom also meets the seductive Susan Atwell, the two who embark on a relationship which blossoms into love on both sides. It isn't until they fall in love that Susan discloses to Tom that she is Brice's kept mistress. When Brice discovers that Susan is seeing another unknown man (Tom), Brice accidentally kills her in a fit of jealous rage. In an effort to protect Brice against being charged for murder, Pritchard devises a plan that they will pin Susan's murder on a suspected but unsubstantiated Soviet spy, code named Yuri, who would have used her to gain intelligence into US military secrets. Yuri is to be whoever was Susan's lover, who they are unaware of is Tom. When they hand the case to Tom to investigate, they do not tell him that Brice was actually the one who killed her. During the investigation, Tom has to protect himself against anyone who may find out that he was Susan's lover and thus the suspected Yuri while finding out who really did kill Susan, which may be difficult if only because of Pritchard's goal to protect Brice at any and all cost, no matter who gets in the way.