Elle, looks like you've got your work cut out for you. If I may give you a few pieces of advice that were useful for me:
- if spouse is not on board, start with your closet and see if he doesn't take interest (if you share a closet, ask him to demarcate his area and leave it alone).
-Anne's advice is how I did it; the maybe box gets taped up and thrown in the attic (on porch, etc) to be looked at in 6 months. I would add another box to this, as I know you have a big family- if there's anything you're saving for kids or someone else to use, that's another box. My daughter and I wear pretty much the same size and that was an excuse for me for a long time, saving pricey clothes for her to wear. But it doesn't need to be in my closet right now, so it went into the storage area too.
- another box, being permies, might be "needs fixing", if you have enough of those things.
- that maybe box, if you haven't looked at it in 6 months it gets donated or repurposed, no need to even open it if you don't want to.
- if you sew, and have clothes you want to save for that, get a basket or something and keep those clothes somewhere else, not in your closet.
- during this process, put on some music, hydrate, and try to keep a good rhythm going. Anything that has tags on it, is not your size, has a spot, just doesn't work for you, be merciless. It's not helping you in that closet.
Good luck and godspeed!!
(when people give you clothes, if for some reason you can't stop it from happening, you can put them directly into your donate stream. If they give it to you and you don't put wear it the very next day [happily, not out of obligation], it's probably not likely you're going to wear it ever.)