Until 6 months ago my husband and I had 2 cats we rescued from the local Humane Society. One was larger that the other and loved sleeping with us. If the smaller cat jumped up on the bed and saw the larger cat there she would turn around and jump back down. They did get along great, played with each other and cleaned/groomed each other. 6 months ago the larger of the two passed away from cancer. The smaller one now sleeps with us and seems to be really coming out of her shell and becoming more and more affectionate. My dilemma is that I have been asked to adopt a 6 year old, neutered and friendly, from what I am told, because the owner is having health issues and does not want his cat to go to the HS if something happens to him. My hesitation is that our cat is finally becoming confident and I am afraid that if I bring in a large male cat into our home she will revert to her previous behavior. She is not a bad cat but I have enjoyed her becoming friendlier and I don't want that to change. And, since I work long days I don't want to come home and find that they have fought or the newer cat will have torn up the house. Advice?
Worse thing you can do is to bring the new, older, cat into your house. After a month or so if you want a cat friend for your cat, get the opposite sex and younger.