I had this problem with my first DD. I had to lie with her (aged nearly 2) every night until she fell asleep. I was at my wits end as I had no evening, never saw DH in the evenings.
We had a fantastic, very consistent bedtime routine, calm, stories etc. Everything that everyone else advocates.
I tried crying it out for 7 successive nights where I left the room, went back after a certain number of minutes. There was no sign DD was going to ever give in.
I wept at the HV and she told me crying it out doesn’t work on the really strong-willed ones.
HV told me to try something else. Basically this. Use all their friends from nursery/ their cousins names. Here’s the script:
“Put your pyjamas on. Jasmine is putting her pyjamas on. Sophie is putting her pyjamas on. Etc etc. (Repeat for all the other children’s names - 4 or 5 is good) It’s pyjama time for all the children”
“Lie down. Lily is lying down, Sophie is lying down, Amy is lying down etc etc
“Your mummy is tickling your tummy, lilly’s Mummy is tickling her tummy, etc etc”
This is all done in a really slow, gentle, monotone voice. Once you’ve gone through everything, start on this one:
“I’m going downstairs to fill the dishwasher. Lily’s mummy is filling the dishwasher, Sophie’s daddy is filling the dishwasher. Next I’m going to do the ironing..... etc etc
It takes a long time to go through everyone and everything. It took my about half and hour but this was much less that the 2 hours I had been spending in there!
My DD just stayed in her bed! It was freaky. She also went to sleep quicker as I wasn’t there. It was like she just understood that it was what you were supposed to do and everyone else was doing it, rather than she was the only child being made to go to bed!
Also, we talked a lot in the day time in really simple language about sleep making energy. How you can’t do the things you like doing if you didn’t make enough energy. Every morning I asked her if she made lots of energy and she would be very pleased with herself for making loads and then I said that’s fantastic we can go for an extra (insert treat that need energy-eg extra 10 minutes at the park) as you’ll have enough energy.
You have to be patient and go through the whole story EVERY night and you have to be relentlessly consistent. It you aren’t consistent or don't like a routine, this is not for you.
Good luck OP. Don’t feel guilty about how desperate you feel. You just want them to sleep. That is normal x