Male cat sprays when routine disrupted
Basically as the title says, my boy keeps spraying whenever his routine gets disrupted.
Some background, he is prone to stress-related cystitis, which lead to an operation 8 years ago to reroute his urethra, keeping it short and wide.
I have two other house cats - his sisters from the same litter. They get on well.
He has seen the vet in the last week and nothing was of concern.
Recently, our daily routine has become so solid, that if I step out of line he'll literally rage-spray (but due to his operation he just shakes his tail while pissing on the floor).
Last night it happened again. I needed to go to bed, but my partner stayed up to finish watching a movie.
Boy cat saw me go upstairs, went into the livingroom to shout at my partner, then when my partner didnt get up off the sofa, he sprayed on the mat - where my partner could see him.
We're due to go away for a few days soon and I have a friend coming over to watch the cats, so obviously their routine will be totally different during this time.
Not sure what to do.
Also, they have water points and feliway plug-ins GALORE.