VioletSky
Are they inside cats?
With inside cats I would get more litter trays and that would usually resolve the problem as they will not want to share
I'm assuming the male is neutered?
If he just wants to mark his territory, that's normal cat behaviour with an intruder cat
Otherwise it could be anxiety in which case, something to ease anxiety like feliway would help
Also, lots of rewards for being close to new cat. Associate new cat with positive additions to the "colony"
Sensible advice. I had two cats, one indoor ( Burmese) and one allowed outdoor ( British Short Hair: far more road sense!). The latter used to pee everywhere. They both shared a litter tray and were fed in the same area. In retrospect I should have separated their eating areas and litter trays. And would have tried using a feliway plug in, although once the habit had become ingrained it probably wouldn’t have helped. They also had an outdoor pen that they both had access to, and that had a litter tray in it. When all of my cats had access to outdoors and no litter trays I never had a problem but I lost so many on the road I had to have a re think.


!