I live in a 2 bedroom apartment with a roommate. I have a male cat (who I'm about to get fixed soon). He's been the only animal around since I got him, and it's about a year old. He's starting to show signs of, well, mating. I'm on a second floor apartment, and I've never let him outside. Although he was originally found outside as a kitten.
Meanwhile, I have a girlfriend who's considering moving in with me. She has 2 cats, male and female, both fixed. She plans on bringing these cats with her.
My cat Butters is free to roam anywhere he wants, and his litter box is in the laundry room, and food/water is in the kitchen. And he sleeps in my bedroom. I keep all the doors open for him, except for my roommate's bedroom.
See where I'm getting at?
The only way I see this possible is to keep Butters constrained to my bedroom, move the litter box, food, and water into there, and let the 2 new cats roam the rest of the apartment. Since Butters spends most of his time in my bedroom anyway.
But then what? How should I introduce them without a fight?
Months ago, a friend brought their female cat over to visit. He didn't like her at all, and hissed and groaned and almost started a big fight. He's territorial.
The 2 new cats get along together great, and come from a place with other cats. They're used to the outdoors, too.
So that's 2 domestically-born fixed male/female cats used to other cats and the outdoors, being introduced to my un-fixed cat which was originally born in the wild but then domesticated and kept indoors.
I feel Butters needs these 2 cats to keep him company and to learn from. But I'm afraid he'll become hostile, since he doesn't know how to be around other cats.
How should I approach this?