I have a one-year-old British Blue boy called Sausage. He is neutered and very calm, sweet, affectionate, and social. I had always planned to get him a companion as he gets along well with everyone and has a lot of pent-up playful energy. He recently spent several weeks at a cattery and made good friends with another boy cat a little older than him. They were inseparable and loved to wrestle with each other.
Shortly after he came back home and settled, I bought a new cat, a female Tabby-something, 6 months and unspayed. At the pet shop, she was napping with dogs and grooming her cat companion, so she seemed really chilled, confident, and friendly. I bought her home and gave her her own room with her own litterbox, food, toys, etc. I am calling her Peach for now. I gave her a few days without Sausage to acclimatize and bond with me and explore the house. She is still quite skittish but affectionate to me (enjoys being pet and likes to sleep on laps) and plays by herself.
However, she is not too impressed with Sausage. The first intro involved lots of hissing and growling on her part and avoidance. Sausage was his normal curious self and immediately wanted to be friends and play. She gave him (and continues to give him) signals to back off and leave her alone.
Anyway, things have really improved on the growling/hissing front, and now they can be in quite close proximity without altercations. They have booped noses, sniffed each other's butts, slept/relaxed near-ish each other, eaten next to each other. She walks up to him and sniffs him but runs away/growls if he responds too much. She still growls, hisses, and smacks when he tries to play with her, which might involve him playfully pouncing her or swatting gently. She is particularly aggressive on the new cat tree I bought them. She tolerates him, but is not enthused at all with his playing and not extremely interested in him. At night she goes to her room as I still don’t want them together unsupervised, and she enjoys her alone time.
It is very early days (less than a week) and I think it’s a great sign that they can tolerate each other so early on. I’m confident Peach’s aggression will improve with time, but I’m not sure she will ever want to play with him or be affectionate with him. Maybe I’m being dramatic, but I wanted a companion for Sausage, not a roommate situation where they tolerate each other. They are both sweet lovely cats, and Sausage is really very loving and playful with other cats if they accept him.
TLDR: Has anyone had cats who have had a lukewarm introduction, where they’ve gone on to be good bonded friends? Could her being unspayed be contributing to her aggression?