@Longingforsummer583
I really feel for you. I am in a very similar situation but I am actually now separating from my DH. I started a thread about him being at home all the time here if you're interested:
https://www.mumsnet.com/talk/relationships/4894767-dh-never-leaves-the-house?reply=129148494
It is so hard to be in this situation. I also thought about all the potential options - getting a garden shed for myself, camper van, even renting a room somewhere that I could go to. But the problem was that I would still be at home for some of the time, as obviously I want to see the dc, and I have to do the housework/ maintenance/ gardening etc as DH doesn't do any of it. Any time I put my key in the lock of the front door, my heart sinks as I know DH will be there, with the depressed energy that seems to surround him.
DH spends all day lying on the sofa or pottering around. When I've been absolutely desperate for some alone time, he'd agree to go out for a walk or a coffee by himself, and at some point I'd get a phonecall "Can I come back yet?". It's absolutely desperate.
I realised around Christmas that I just couldn't carry on like this for the rest of my life, however much i wanted to keep the family together for the dc, and the worry about finances. It is an utterly stifling and soul destroying way to live. There has been a lot of upset on both sides, but to cut a long story short, we are now separating and DH is moving into a flat.
What has really hurt me though is that now he has to move from the sofa and sort some things out, he is doing it. He is getting flat pack furniture for his new flat and putting it together. I have asked him for years to help me do things like that and he was always too tired or depressed. He has bought a lawn mower for the new place, whereas at our family home he very rarely mowed the lawn as he "had no energy". I actually feel now with my DH that he has been massively in his comfort zone, and basically wasn't doing things at home because he didn't want to, and could get away with not doing anything.
Re your financial position. I am in a similar position to you. We are currently talking to a mediator, who is also a solicitor. She said that in our position (I was a SAHM for years but now working, DH worked and was the higher wage earner for years but now not working) that it would be likely that finances and custody would be a 50/50 split if we went to court. My DH was dead set against speaking to lawyers but he has been ok with mediation, it seems less adversarial I guess.
I am thinking of you - it is an unbelievably stressful situation to be in.