My DS still has a day sleep at nearly 5yo! hehe. I put both DS & DD down for a sleep about 11.30am.. any later and they don't go to bed at night. They can both stay up all day, but it takes it's toll after a while... and they are not pleasant to be around! So where we can.. we still have day sleeps in this house If they don't fall asleep I don't force it (usually LOL.. unless we know we'll be having a late night or something).

We don't have a strict night routine, but generally (when DH is at work etc) it's dinner at about 5.30-6.00. Bath. Pick up DH. Then he does the bed routine of toilet & brush teeth. Sometimes he'll fool around with them, or read a story or something, so bedtime is probably on average 7.30-8.00. DS sleeps right through til about 6.30. DD wakes up some time through the night and climbs in with us (usually without us noticing). Just this morning I was thinking I might start walking her back to her bed through the night (if I notice her come in) because it'll be easier when the bub comes if she's stays in her bed.

We make a big fuss praising DD staying in her bed ALLLLL night when she does.. and every night she says she will again, but doesn't usually. She is usually waking up thirsty, and I have before settled her back in her bed with a quick drink and cuddles good night again. But co-sleeping really was our saviour when they were constantly waking in the night, and we just went with that so we could all get some sleep. They do sleep through in their own bed eventually. And tbh.. I don't think you've done anything wrong. Getting off to sleep and staying asleep are very different IMO. My kids weren't great at staying asleep either. Not too hard to get to sleep.. but just didn't stay asleep. It definitely got better as they got older, and I've found it's easier not to fight them with it.

Funnily enough.. DS started sleeping through properly once he was dry at night. I have a sneaking suspicion this could be the case with DD too.. that it might be her bladder waking her... tho she's not taking herself to the toilet through the night cos she's still in a night nappy. Some times she is dry in the morning.. and sometimes she sleeps through.. hmmm... I've never actually worked out if it really is related.

Just re-read your post. Re the sitting with him to fall asleep... we did this for a long time too. Once it started taking a long and frustrating amount of time for them to go off to sleep, we started getting up and leaving. I'd say.. ok.. mummy needs to go do something (toilet or something).. I'll be back in a few minutes. they'd wait for me.. and when I got back I'd heap LOTS of praise on them.. oh you're such a big girl staying in your bed! I'd sit for a little bit longer.. ok.. mummy needs to go and do a few things in the kitchen.. i'll come back and check on you ok? Took a little while to reduce the amount of times I had to go back.. but there was no tears.. just lots of praise when they stayed lying down in the bed alone.

Don't know if any of that helps... but just know you're not alone with a waking toddler