Get rid of the cat. Or, if your spouse is allergic to your cats, get rid of the spouse. He has also seen many cases where people refused to get rid of the cat or the spouse. Here are some things that may help. Bath the cat regularly, even if it is just a bath in distilled water, or plain water.
Dander causes most cat allergies and is produced regularly.
If you keep it washed off, it can make a big difference. There are many different kinds of air filters. To help with allergies, you need a good one. And you need to leave it on all the time - not just when the furnace or air conditioner is on. Some of these people find that after being away from cats for a protracted time, their allergy returns the next time they get a cat.