OP, I don’t think you are being unreasonable or the problem.
I was recently thinking how people judge what they see, they often have no idea what you experienced or experience.. even in the same family.
I don’t know, but you may have started from minus - 30, with support, help growing up.. and you’ve climbed to + 20. Someone who has help might have started at + 15 and climbed to + 21 and think you are a pain. I know these numbers probably don’t make much sense (made up to illustrate,) but I mean to say that the effort and growth you may have done in your life may be huge, but others don’t see it. They may have had advantages etc.. and all they see if you are struggling more than them.
I feel for you and hope you are ok. Talk to your friends, ask them gently perhaps their thoughts.. try to focus on other people. Take steps each day.
Wishing you the best, your were brave to ask your husband to go. I hope you have support, care and success surrounded by you.
And on a practical note, do you have ‘Homestart’in your area. You could ask your health visitor, even if your children are quite grown. They are an independent body, I understand, not connected to social services etc. They could maybe help you round the house, a friendly person to talk to every week or every other week, whilst you go through this transition xx