Reading your post was almost spooky for me because there are so many similarities in our situations. Well, actually, only a couple of similarities, but they are major ones: I'm 44, hubby is 46. You could be describing my husband in a LOT of ways. Differences: we don't have children, but we do have his 86 year old father (hubs is a carbon copy of his dad). My husband works (most of the time), but for minimum wage or not much better. My husband is a sentimental hoarder so we have more stuff than you guys. But I moved us to a smaller house because I couldn't manage the bigger one with no help. I have frequent anxiety about what will happen to our lives if I get very sick. I handle all the money, all the bills, most of the heavy lifting on housework. He was so bad at yard work, we have to pay someone because I work 7 days a week and we were an embarrassment, even in our dumpy little neighborhood. My husband is not bipolar, but he is ADHD and super dependent/clingy. I even stopped doing the dishes! I make him do most of them, because when we "take turns" it's a joke. I do it 4 times a week, he does it once. When I do it, I'm doing all the stuff he didn't get around to when it WAS his turn, etc etc. so essentially, I would empty the dishwasher, fill it, then hand wash just as many dishes that wouldn't fit. I quit doing dishes and I refuse to cook unless the kitchen is clean. I just can't handle it anymore. And mostly I feel like a parent and am no longer sexually attracted to my husband. Not repulsed or anything - just not particularly interested 99% of the time.
Anyway, last year around this time, I found out my husband had some inappropriate text/phone relationships with a couple of women. There was no sexting, but it was not appropriate. I kicked him out for a while. The reason I'm telling you is because it absolutely did open my eyes to the misery that is my married life. We are back together, giving it a go, but I remain ambivalent and it's not for the inappropriate stuff (he is so needy, it's sad more than anything) - it's because I feel like I only have 1/3 or 1/2 of a partner - not a whole partner. And I can tell you that you ARE enabling him. And I can tell you that even if you make major changes, you should expect things to improve at an incredibly slow pace. If these guys were good at personal insight, they wouldn't be so dependent/unstable.
You can stop caretaking him and you should, or he will end up like my FIL whose wife passed 3 years leaving him all alone and totally incapable of life on his own. He has made a mess of his life, despite my husband and mine's heavy involvement. No one thought his wife would pass first and no knew just how much she kept it all together for the family. But I know now. I know it only too well.
And you know what's funny? My husband's standards for his father are so totally different than the ones he has for himself. And he is 100% not aware of it! It's remarkable. LOL
You aren't helping him by sheltering him and enabling the behavior. If you die, what then? How was it a help to him then?
I don't want to keep going on endlessly, but seriously, I feel for you. We are somewhat kindred spirits.