I just want to make it completely clear that, this is obviously based on my very limited knowledge about your situation, so if something doesn't feel or seem right for your current situation, that is most likely why, so it is purely based on what you have told me earlier and what you write here, mixed with my own interpretation.
I think it might be ok for you to maybe get an objective point of view on it, because when you are experiencing something like this, things might not see or you might not notice things as clear as when not standing in the middle of it. So when I say that it might not be as bad as you think, I don't mean the general situation, that is obviously not good.
But since I don't know your husbands perspective and only yours and what you are writing. I think, you have to maybe take a step back and try to look at things, a bit differently, and maybe take the bull by the horns so to speak. Because to me, it sounds like you two haven't really talked with each other for a long time, and I mean "really" talked.
So if I were you, I would go see him and simply put it to him straight and ask him if he is interested in you coming by and visiting him or essentially having any further contact with you or if he would rather be left alone, making sure whether he have made up his mind about the situation etc. Said in another way, get some sort of closure or final conclusion.
You said that you don't have many people in your life, which is obviously not fun, but it is not something which can't be solved. And from how I understand it, your husband, despite you two might not have been getting along the best, he at least gave you someone. Which I could imagine is probably also why you feel down at the moment. But on the other side, again based on what you have told, maybe there weren't really a lot in the first place? If you care to be around other people, you want to be around people which you enjoy being around and makes you feel good etc. But it doesn't seem like this relationship have really offered that, but is more based on the fear of being alone, so you accept a lot of the bad things that comes with it.
Now I personally like being alone, I hate having people around me all the time, I don't like going on long vacations and I get bored of spending to much time around others fairly fast. Not everyone have it like that, but I know plenty of people that live alone, including people which have no children etc. and are very happy about it, because it gives freedom. I even know, yet one of them is dead now, people that were married, but didn't live together, so they had separate apartments, but whenever there were parties etc. they showed up as couple and did things together as you would expect married people to do and it worked well for them.
So in your case, since you have the Bahai community or it might not even have anything to do with them, what you could do, is maybe join a group to learn to cook, gardening, paint, writing, singing, gospel if that is a Bahai thing, something with cats, whatever you think could be fun and then meet new people through that. And if you are lucky you could make some new friends.
Alternatively, you could do charity work, maybe if there is something in the community that you don't like or you know could use some help, you could start an event to do something about it and maybe some will join you, maybe from the Bahai community or just some evil atheists
and you can meet people like that. And lets be honest, there might very well be other people in similar situations which are also looking for someone to hang out with. So I wouldn't be so down about it, because there is a lot you can do fairly easy if you want to meet people and feel that is very important.
But to me, if I were you, I wouldn't spend so much time of what went wrong between you and your husband, that is what it is, and again it might sound easier than it is, but I would try to get some form of closure, you don't have to break all contact with him unless he say that this is what he want. But I don't think you will win anything from trying to keep on to something, which might not even have been there in the first place, which might only give you a "false" sense of it being there.
So it might be good for you, to sit down and just try to take a step back from everything and look at it from a wider objective perspective, and try to put your personal feelings to the side for a moment and look at what options are there and simply realize that there are certain things you just have to accept for what they are, whether that is your husband's choice, that your brother might not be very nice, I mean you are not forced to keep contact with him or put anything into it. Because again, I don't think you would have a hard time finding some people to hang out with, that are looking for the same thing as you and as you said you are already used to taking care of everything, so at least that doesn't change.