Penelope, no advice I'm afraid, but big hugs and lots of sympathy. Your DH sounds rather like my OH on the won't/can't get up/just leave them to CIO front. He also thinks it is my fault because I wouldn't do CIO at six months (or ever for that matter - I just don't believe in it).
What I do know is that any form of sleep training/night weaning etc is about a million times harder when you're on your own doing it, and not getting any back up or sympathy.
My DD1 (26 months) does now sleep in her own cot, in her own room and sleeps through some of the time - it goes in phases tbh, we had nearly three months of great sleep (maybe one wake up and quickly resettled two or three times a week) when DD2 arrived four months ago, but are now back to at least one wake up a night, and sometimes a long time to resettle. Its pretty hellish with DD2 feeding 2/3 times a night as well and I had a complete explosion at OH this morning for not taking the kids and giving me a decent lie in on the one day a week I can get a bit of a break. 45 minutes of extra sleep! FFS.
I would say stop giving yourself such a hard time, you are doing a great job - just getting through each day with a sleepless toddler is an achievement in my book!
I can't actually remember how/when I night weaned DD1 - it is all such a blur. I know that by 16 months she was just having a late feed about 11 and an early morning one about 5, and I think we dropped them around 18 months when she seemed ready. I was keen to stop BFing her a few months before her sister arrived though so encouraged her to stop by offering cows milk first and only feeding if she was insistent. Would your DS take a bottle instead? And then gradually change to water/cut down on the amount? My DD1 takes a non-spill cup of water to bed and I do hear her drinking occasionally when she wakes up.
Re getting her into her own bed, I gave up co-sleeping at around 9 months, as she was just so wriggly, I was getting less sleep than ever. I had always settled her in her own cot at the start of the night, firstly in our room and then in hers. So I put her cot at the end of the spare bed, and bed-hopped all night, starting in my bed and then moving into the spare bed when she woke up. Often she would end up in with me in the spare bed but at least we both had more room and slept a bit better. When we moved house, I put a mattress on her floor and did the same. Many nights, I could only get her back to sleep by holding her hand through the bars. Eventually I managed to succeed with gradual retreat training (on about the 10th attempt!), firstly getting her to self-settle without any intervention from me (I used to lie on her floor and pretend to be asleep to try and demonstrate what she was supposed to do!) and then moving further away during night wake ups.
Now if she wakes, I go to her and check her (she has had a lot of illness and teething lately, and now seems to be having the odd nightmare), then stand outside her door saying "shhh, back to sleep" until she calms down then quietly move away. If she makes a noise while I'm moving, I stop and repeat until she settles again.
That's all assuming DD2 doesn't wake in the meantime and start howling in which case it all goes to pot!
Sorry for the very long post/rant - hope it helps to know there's plenty of us out here in sleep deprivation land! (And if you're still not sure, check out the Misery Loves Company thread!).