First the movie is pretty old. Im thinking it was made in the 50s-60s, it was in color. Its an american film, I watched it on AMC many yrs ago so the details of it are a little shaky.
It centers around a dark haired women i think she was italian. She was a popular singer in her town I believe.
A talent scout discovers her and she becomes famous. Eventually she falls in love and marries a man. hes a Count or has some type of royal title.
After marrying him she finds out he was injured during the war and can’t perform. (He’s impotent)
Of course she devastated but loves him anyway. She knows having kids with him is out of the question now. so she secretly has an affair in order to give him a child.
The husband finds out and kills her and i think the other man too.