DD is 22.5 months old. She slept and self settled beautifully as a baby. In the evenings, we would pop her in her cot awake but sleepy, and she'd fall asleep happily and stay there all night. When she was 16 months old, she started a massive sleep regression which has never ended. She refused to go to sleep on her own in her cot. DH works evenings and I was pregnant and working full time, so she ended up sleeping in my bed a lot, just so we could get some sleep.
Fast forward to now and we have an almost six week old DS who sleeps in a crib in our room, occasionally in bed with me if I can't settle him in the night. DD refuses her toddler bed (cot converted and new bedding bought with great aplomb and she slept in it for 2 nights) and she refuses the single bed in her room too (DSd's bed) and the only way to get her to sleep is for DH to co-sleep with her in the spare room, sneak out once she is asleep, and be on hand in case she wakes up. It used to be me that did this, but since DS was born, DH has had to as I spend all evening feeding a colic-y DS.
I don't know how to break the cycle - she screams at any attempt to get her to sleep in her own room. Are we just going to have to bite the bullet and put her to bed on her own, stick a stair gate on her door, and leave her? I think she is too young to understand stickers/rewards.
I don't think we dealt with the 16 month regression well, and have now set a very bad pattern/routine. Any advice gratefully received...