Methods for helping toddlers sleep on their own
I have 3-year-old twin boys. We sleep trained at 7 months, one slept intermittently through the night, and one never was able to do it. Starting at about 2, I just kind of gave up and let them sleep in my bed because I needed to sleep. It's been great. They start the night in their own bed and then cry for me between 10:30pm-1am and I go grab them and pull them into bed with me, and then we all sleep solid. Their dad is a shift worker, so he's not home a lot at night anyway, and he has just been happy that I'm better rested now.
The problem is, one of our twins is now not sleeping well if I'm not there, so we need to figure out a way for them to start sleeping on their own so I can go on work trips, girls trips, etc. and know that whoever is taking care of them isn't going to be up all night with a screaming toddler.
Any tips? I'm dreading working on this because I've now gotten used to sleeping 8 hours and am not looking forward to having to work on sleep again, but I don't think I have another option.
FYI, I will absolutely not be leaving them to cry in their room. I understand if that has worked for you; we did CIO at 7 months ourselves, but at this point, it is not a fit for us, so you can pass that advice along to someone who will be more receptive to it.
TLDR: I need tips (no CIO) for helping my 3-year-old twins stay in their beds all night.
Thanks!