A Cat Problem

We have one problem with our new cats. Fervor, Martha's cat, and Cleo do not get along. Fervor looks for Cleo and she screams and hisses and both cats get some scratches although Fervor seams to get the worst of it. You would think he would stop going after her. He even looks for her when she is hiding under our bed. Hubby chases Fervor off but then Cleo takes off after Fervor. Cleo loves Hubby and the feeling is mutual, so he protects and defends her. Hubby built a door in our hallway to keep the two apart, but Fervor cries when he is confined. I take Fervor into my sewing room with me and close the door so he has company but cannot get at Cleo. Our life was so much simpler before. Hubby loves cats and I don't think it would be wise to ask him to choose between me and the cats.