I totally get what you are going through as I too often feel like that with my husband's mental health (Mixed Personality Disorder and OCD). Like you, I often feel like it is a one way conversation in our house where everything is about him and the only time it is about me is when he criticises me. So a lot of what you have said does strike a chord with me and I totally sympathise with you.
Nobody expects you to be a saint, but it does sound as though you are supporting your husband really well. It isn't good if you are feeling isolated as this will only make you feel miserable and you need to look after your physical/mental well-being in order to support someone else.
Last year I sought some help for myself. I would suggest you maybe either speak to one of your family or a friend about how you are feeling or even, as I did, go to speak to your GP about things. There is help out there. I went to a Counsellor for a while to discuss how I was feeling in terms of coping with my husband's mental health and how to better approach it, but I realise counselling may not be for everyone. From that I was referred on to my local carers centre and Support in Mind and see a couple of support workers from there. Maybe try to find a support group for carers of people with mental health issues either in your area or online where you can speak to others who are going through a similar situation to you as this does help a lot. On here, of course, is great too for speaking to people, although it can be a quiet forum at times.
I know walking on egg shells can be so stressful and can just wear you out at times so you do need some kind of outlet to take you away from focusing on your husband's mental health. Also if you have any activities or hobbies you enjoy doing that is great for giving you a boost. I would be lost without my knitting group and going to Tai Chi as some time away from the house does refresh you. Also try to see family/friends as much as you can for your own enjoyment.
I hope the above helps. Other people may have some other ideas too. If you need someone to speak to I am on here from time-to-time so am happy to chat. Wishing you and your husband all the best. Aileen x