Spay/neuter? That's weird. My doc said you were allergic to the saliva, and neutering my cats never changed a thing.
I'm allergic too, I did the shots thing for 7 years, before my doc gave up on me and told me I would never get rid of my allergy to cats. Although it's slightly better now, but I stopped the shots 7 years ago anyway. It started when I was 5 or so, I started getting allergic to everything that is furry, from hamsters to horses. After getting the worst grades at school for years for not being able to run without getting too much asthma to continue a teacher finally told me to go see her doc, who is a specialist in allergies. It probably saved my life, and when I did the testings at the hospital they didn't want me to leave, lol.
Long story short, it's manageable. I have all kinds of symptoms, respiration problems being the worst, from asthma to a kind of chocking, when I can't fill my lungs. It happens a lot still, but it mostly depends on the weather. I also get stuffed nose, itchy/running eyes... I used some nasal spray last winter for my nose (3 months without being able to breathe through my nose before I got fed up and went to see the doc, who of course told me to get rid of the cats), otherwise I use zyrtec when I have itchy nose or eyes, and I use advair and albuterol for the asthma. When my lungs get really messy and I start coughing, tussin DM syrop works wonders.
It still sucks sometimes, but it's not bad enough to make life impossible. And yes, you get used to your own cat after a while, it's not really different from getting shots every week to get you used to it.