A largely forgotten film noir that copied a lot from the Hitchcock classic Rebecca 

The Second Woman
(1950)

Jeff Cohalan (Robert Young) is an architect. His fiance, Vivian, died the night before the wedding, in a car accident with him driving.  He lives alone in a hilltop mansion by the sea.  He meets Ellen on a train.  Ellen is coming to stay with his neighbor.  She falls in love with him, but he is distant and pre-occupied.  Jeff still works closely with Vivian's father, Ben Sheppard.  A large new hospital is being built, and Jeff is hoping to be selected as the architect for the project.

Jeff has been having a strange string of bad luck in the year since Vivian died.  His horse dies, his dog dies, a valuable statue falls and breaks, his rose bushes die and a valuable painting of Vivian has faded.  Finally, his hilltop mansion burns down.  His bid for the hospital project is also sabotaged. The town doctor warns Ellen to stay away from Jeff.  The doctor thinks Jeff has been driven insane by the guilt of the accident, and is himself responsible for all the other mishaps.  Ellen refuses to believe this. However, the more she investigates, the more odd Jeff's behavior seems.

Jeff is convinced someone else is out to get him, but only Ellen believes him.  Jeff fakes a suicide attempt to throw off this supposed enemy.  He then gets a breakthrough.  When he took his painting to an art dealer, trying to figure out why it was fading, the dealer mentions that he ran into this before.  Someone took a painting by the same artist, and faded it with special lights.  Jeff had been trying to track down who bought and faded the other painting.  He figures they bought it as a test to find out how to fade Jeff's painting. He finally gets a call back telling him who had that painting.

Armed with this knowledge, Jeff confronts Ben Sheppard, the father of Vivian.  Ben admits that he did all this because he holds Jeff responsible for the death of his daughter.  He wants to ruin Jeff's life.  Ben tells Jeff that Jeff is still doomed, as no one will believe this story.  Just then, Ellen bursts in with 2 men.  One is Keith, the town playboy.  The other is the driver of the car that crashed into Vivian's car.  Jeff was not driving when Vivian died.  Vivian had carried on an affair with Keith all through the engagement.  Keith convinced her to run off with him that night.  They left with Keith driving Vivian's car, and Jeff following in his car.  After the crash, with Vivian dead.  Jeff wanted to protect Ben from knowing what his daughter was really like (since Ben's wife had affairs and ran off).  Jeff took responsibility for the accident.  The other driver went along, since he was afraid of being blamed for the death.  With this revelation, Ben loses his mind.  Ben imagines that Ellen is Vivian, and wants to kill her.  He pulls a gun and shoots.  Jeff jumps in the way, saving Ellen.

The movie ends with Jeff and Ellen together as he heals from the gunshot wound to his shoulder.

Thanks Joseph C!