DS2 wouldn't sleep without me, and did the same as your DD - he would scream until he made himself sick, and wouldn't be settled by DH. I had tried gradual withdrawal too but to no effect, so dh invented his own method.
DH started on a Friday night (so that he could sleep the next day) and put a matress in with ds. When ds awoke, he kept the light out, said "Mummys asleep. It's dark. It's sleep time now." He lay down beside ds2 and pretended to go to sleep, repeating that phrase every 30 seconds or so.
DS2 screamed for a loooong time. We knew that he wasn't ill as dh was with him. We knew that he was safe, but he still managed to scream for 5 hours+, with dh repeating his phrase on and off!!
The next night he cried for 20 minutes. The third night he whimpered once, and then all you had to do thereafter was repeat "It's dark. It's sleep time" and he snuggled down.
That first night was one of the longest of my life. We could only do it as dh was in there, to reassure me that ds wasn't vomiting. If he did, dh said he would clean him up and then go back to reassuring him. I honestly couldn't have done it for a second night but luckily we didn't need to.
The advantage of sleep training when they are older is that you have language on your side. At 19 months, you could start to build up by using the phrase "Sleep time" every time your dd is going to sleep. See if you can establish the word as a trigger that she recognises, and then get dh to take over.
Best of luck. It really does change your life when they sleep through.