my male cat still fighting

Question
hi,
I have two Persian cats, a male and a female, they are 3 years old. my male cat is neutered,he used to bit and fight with the female. now after 90 days from his surgery for neutering he still keeps fighting with my female cat. they have mated many times before but when the heat period of my female cat was finished he started fighting again (!) .wherever he sees her,he attacks and bites her. my female cat just escapes and cries.I'm really tired of separating them all the time . none of my two cats can tolerate staying in a room,so that all night we must hear grown of cats.
I thought after neutering a cat and after one or two months everything will be ok but now after 3 months...
please advice me how to calm him down and what's the reason.you can also be sure that in our house there is no difference between my two cats. there is sufficient attention for both of them.
thanks

Answer
Have you had them both from kittens and which one came first? It sounds like you've had this problem from the beginning? It's a fact that unneutered males feel the need to fight when they can sense another tom around. And even though you had him neutered, he's still set in his ways. I don't pinpoint a time line when it comes to waiting for a cat to lose his hormones. But if this has been going on from the kitten stage, I wonder if it's something genetic. Because typically a male cat will only want to act out his aggression towards another male. Do you feed and water separate and do they have separate litter boxes? If not, I would start with that. I would also keep a water bottle handy and simply squirt him when he starts to act up. It's completely possible that he just may not like her. That's why I would feed them separate. Is there certain circumstances that seem to trigger the fighting? Is the female spayed now as well, because that might be an option, to eliminate all hormones in the house.