I'm really torn with this one. Obviously I agree with everyone that your behaviour to your DH was unreasonable, but I'm sure he'll forgive you.
I'm torn because on the one hand I want to say: Please, please try to step back a little and imagine what your day to day life would be like if you were to introduce some formula. I truly do understand why you are so reluctant to do this. I have my own tale of woe about breastfeeding, combination fed, and expressed several times daily to boost supply, for over 6 months. I don't regret it, but I was very, very careful to take my child's cues. At a certain point I could see that she simply was happier taking the larger, less frequent bottles than the shorter, frequent breast-feeds.
If your baby really is BFing round the clock at 4 months, then the supply/feeding problems are affecting her. She does need to do more than feed now.
On the other hand, I also know what it's like to have PND, and it's entirely possible that your first post is not totally representative of your day to day reality. If you can honestly say that your LO has lots of happy periods every day when she's well fed, alert, taking in the world around her and learning to move around, and if she's growing at a reasonable rate - if you can honestly say all that, then I don't see any problem with carrying on as you are (but I would strongly suggest you forget expressing if it's only to build up a freezer stock - seriously, sleep is far more important)..
But you should only do so if you are happy, and you're not damaging your relationship. It does sound as though your husband is getting quite a rough deal. Not to mention your nipples sound excruciatingly painful. Don't martyr yourself - your baby needs you to be happy and healthy, far more than she needs your breastmilk now.
Gosh, that was long