<human>: Could you distill the essence of the text into 1-3 sentences?

As the title says, our neutered male is still marking.  We have three cats in total, 2 spayed females and the male.  One female and the male fight often and don't get along generally but it's not always that way.  The female marks as well and outright just empties her bladder whenever she sees fit.  She rarely uses the litter box at all.  The male will use the litter and we've noticed that most of his peeing behaviour is marking.
This has been going on for some time now and we are faced with some home renovations for flooring that we are postponing because of the destruction caused by the marking and spraying.  
Here are some of the things that we have tried over the years, yes... years.  
Pheremone spray, and collars.  Enzyme cleaners, bleach,  peppermint oil soap, white vinegar and steam cleaners.  Different brands and types of litters.  
We have 4 litter boxes as we've heard that we should have one extra than the amount of cats that we have.  We've even tried some sort of spray on the cats fur that was supposed to make them smell similar.
We love these cats dearly, all three were personally rescued by our family. But now we have reached our limit and are faced with trying to find a home for the male or having him put down.  We are targeting the male because when we had a friend house him for 2 weeks, the female stopped completely and was back to using the litter.  Albeit this was a couple of years ago now.

I should also note that the two problem cats were fine for the longest time and lived in harmony until the male got sick and had crystals in his urine.  The treatment for that seemed to trigger the marking and spraying behaviour.

We are still willing to try something different and are open to advice.
<bot>: Male and female are in a pissing contest and are destroying our home and belongings. We have to make it stop.