I totally get part of what you described, my wife (soon to be ex) also didn’t gave me any support when I became depressed after my father died. Worse than not supporting me, she was making matters worse every day, because since she was annoyed that I wasn’t the usual happy, optimistic guy that I was before depression, she was starting arguments on a daily for each and any reason possible. She was getting more and more abusive, the more I got depressed and she destroyed the relationship we had. I will go into more detail on a specific post asking for advice for myself, but now focusing on you, I’ll tell you what I know about someone on your situation, and which things in my experience, you should and which things you shouldn’t do.
Regarding mental health, as you said you already experienced suicide ideation in the past, and since you are depressed, it’s possible that you experience it again. On this specific note, pls remind yourself everyday of all the persons that would be devastated if you killed yourself, and the ones who depend on you or may depend one day. If you cannot find a reson to don’t hurt yourself for you own good, at least don’t hurt yourself for the good of the ones you love and care about. You daughters love you and they need you or they may need you, and probably there are other persons out there, that also love you and may also need you. What would happen to your disabled daughter if her situation got worse and you are not there to help? What if something happens to your younger daughter, if she needs help? Don’t give up bro, your daughters will need you many times in the future, stay alive and step up when they need you, like the great dad you are.
Regarding mental health, on a more general note, seek professional help if you can, but if you cannot afford, it’s not the end of it either. There are support groups with people that can help you, and if there aren’t in your zone, I’ll tell you a bit of what I did to keep sanity at my lowest. I was struggling with depression and financial problems where I live (for now, I’ll change soon). It’s a small town in the country of my wife, I don’t speak the language, all my aquaintances here, are people that I met through my wife, therefore I had no one to speak personally and could not afford mental health care. I remembered that my wife used to say that marriage is like jail, and that’s what lead me to the solutions I found to keep sane. I researched and found that inmates living in highly depressive environments, keep sanity through exercising, writing, reading, and keeping a disciplined schedule. That’s what I did, I started waking up 2 hours before I had to work to exercise, and 2 hours after work. I started reading more and writing down what I feel. That helped a lot. I also started spending more time on my hobbies, and getting in touch with family and friends, and that is what helped the most. I shared what I was going through, the hell that I was living, and people who love me cared, offered advice and stated they would be there for me no matter what. Some where mates I hadn’t spoken with for some years, but they were there when I needed. For your own good, pls talk with someone, don’t let it boil inside you, things that you don’t share seem bigger than they actually are. Another great advice is to go cold turkey on your vices. I don’t know if you are into alcohol, weed, pills, prostitutes, gambling or anything else, (me personally, I had my struggles in the past with booze, weed and prostitutes), but whatever vices you have, pls stop them completely. I had quitted prostitutes and weed years before I got depressed, and I had the drinking habit under control, but I stopped it entirely, not even a drop of beer, and it helped a lot. Other very good advice is, do not take any major decision without discussing it with at least one of the persons that you really trust. Remember that your head is not 100%, so don’t take major decisions without running the idea by someone else whose not struggling with mental health at the moment.
As for telling your daughters what happened, my advice is, pls do if they are grown up. They are your daughters, they deserve to know the truth about their mum, and they deserve to know the truth about you. My mum and my dad told me the things that they did to each other after getting divorced, and although I was too young back then (aged 15), it helped me to understand them. Sure, they looked more flawed but they looked human. They both did mistakes, but they both had a couple of good reasons to divorce. Pls tell it all to your daughters, you owed that to them and to yourself.
As for the thing of the house, try to have it your way on the Court, but if you cannot, don’t overthink it. If your ex gets it her way, after you put up a fight, it doesn’t matter, it’s just a house. If her new guy starts messing the house don’t sweat it, remember he is living with your ex, so he will probably suffer at a certain point what you suffered. Feel bad for the guy, he has to live with your ex on a daily, and if your ex is the piece of work you say, no man deserves that. If your ex is the piece of work you say she is, all I can say is hearts and prayers for that mate, he has some dark times ahead.
Pls remember that there are thousands of men all over the world who went through what you are going through, and lots of men made it through and are now living happy lifes. It’s possible to be happy after passing what you are passing right now, don’t lose the faith in the future.
Good luck at this tough moment of your life, and if you need any further advice, or if you just want to share some more, pls do so, you are not alone.