As a starting point, order the books (and recordings) of Claire Weekes and just listen and read them. She was an expert in helping people with agoraphobia and anxiety in general and it helps just to read about it, feel understood and see others have trodden the same path.
you are trying to convince yourself you don't have a problem as you don't have anxiety in your house, but with phobias, this is typical, I'm only anxious if I see a needle/have a blood test, the problem is the uncontrollable anxiety if you are exposed to the fear object, which for you is the whole of the outside world! My needle phobia is not a problem unless I need to have surgery/go to a hospital, which I have had to do recently- that's why phobias are so difficult because you can end up rearranging your life around them and affecting your ability to function but it may not be noticeable until you have to go out/have a blood test.
In this case, your agoraphobia is affecting your relationship (huge pressure on your husband to function as 'you' in the world), everyday activities (can't shop, starting to avoid work) and causing you stress (why would you write on here about it if it's just fine to stay in and never go out, I think you know this is problematic). It's also quite problematic that you feel it's ok for your ASD children to stay in- what if they start avoiding college or school, or don't make friends?
I think it's brave of you to post, and I suspect you do want to tackle this. Hope it works out for you.