Hi Lillipot, I had to stop co-sleeping at about 10 months due to the wriggling. OH was still in with us too and there was just no room and no sleep for anyone!
So she went back in her cot (although she was already napping in there and starting the night in there). As it was before a planned house move, we'd kept a bed in there as well as the cot so I 'slept' in the bed with the cot at the foot and spent most of each night upside down in the bed with my hand in the cot!
After we moved, I convinced myself she was going to start STTN so just went in and out and sat on the floor. After a month of falling asleep on the floor with just a blanket and waking up cold and aching I got a small fold out foam mattress (like a kid's sleepover one). She then started STTN some of the time (talking books played a massive part in this, we used to leave them on all night) but regressed every time she was teething and I would end up on the floor again with my hand in the cot.
You could move the cotbed but what are you planning to do when baby arrives?
Slightly radical suggestion but if its a small room could you take the cot out and just have a mattress on the floor and stair gate on the door? That way she can't hurt herself falling/climbing out but you can have a bigger mattress so there's room for you (or DH?) if necessary!
If you're on the same page with sleep methods, I would let DH try again, and go out of the house at bedtime if you need to - I found hearing them cry and not doing anything completely alien and really really hard. But she isn't being left alone as your DH is there and comforting her, and its probably more temper at not getting what she wants (you) rather than her being genuinely scared/upset etc. It will also help them form a better relationship which will massively help when baby arrives.
I've been much better this time at distinguishing cries (or maybe DD2 is better at communicating them!) from whinging/cross/hungry/scared etc and its really helped.