tracey, just because you've given up on having your idealistic home and life with him (and they were only ever an illusion) doesn't mean you won't find it with someone else.
If this is your dream, then you leaving him is the only possible way of getting it, because it will NEVER happen while you cling onto him.
Your life seems well rounded, and if you can get through the depression through the temporary use of anti-depressents I bet that things will improve.
I am an introvert and I've suffered from depression my whole life so I know what I'm talking about
Have you considered buying your own place? That way you could have your refuge, and set it up to suit you. I'm a boring mother-type and I kept telling my daughter 'You'll never win the lottery, and Prince Charming will never come and rescue you'. In other words, if you want something done, do it yourself.