Don't give up hope! You must be exhausted, but I have a couple of suggestions you might try. Remember that everything has to be tailored to fit the personality of your little one, but these are techniques I know have worked in the past.
First, recognize that it's hard for adults to quit cold turkey, too! Try reintroducing a sippy cup of lukewarm water that your daughter can suck while going to sleep, and see if that helps her relax a little. You could also try a cup of warm milk before she brushes her teeth for the night.
Next, it's not too late to establish a bedtime routine. This will help your daughter get sleepy. My son takes a bath, brushes his gums, we read a story together, he has a drink of water, we say our prayers, turn off the light, I sing him a lullaby while rocking him, we turn on his "sleepy-time" CD, and I put him in bed. I follow the same pattern for nap beginning with reading the story. No matter where we are, what time of night, when it's time for him to go to sleep, we follow that pattern. It will take a little while to establish a night-time pattern with an older child, but do so now! And never deviate from it! I may be bored sick of my son's sleepy time CD, but that music is his cue, so I still listen to it every night!
Also, no matter how late at night your daughter goes to bed, she should get up at the same time the next morning (don't let her sleep in). If she's overly tired, let her make it up the following night.
Finally, make sure your husband isn't doing more harm than good when he hangs out in your daughter's bedroom. Once you've said your good-nights, turned off the lights, and completed the bedtime routine, there should be NO FURTHER COMMUNICATION with your child. No telling her to lie back down, no reminding her it's night-time, nothing. If she needs Daddy in her room, for now, he can stay there, but if he interacts with her, she will never allow him to leave. So take a couple of nights (probably about a week) with Dad sitting in her room until she falls asleep while you establish the night-time routine, but make sure you don't reward her with attention for staying up. If he wants to stand up to lay her back down or pat her bum or something to help her sleep, that's fine, but he shouldn't make eye contact and he shouldn't say a word.
Hopefully, once she realizes Daddy won't engage with her, his presence in her room will become slightly less important. Once you notice that happening, the next step is for Daddy to slowly begin moving away from her bed. Every night, he should sit a little further from her bed (but still in her room) until she is comfortable with him at that distance. Hopefully within the period of another week, Dad will be out of the room.
One more resource that might help if my advice doesn't work is Supernanny, on TV. I'm not a huge fan of all of her techniques, and of course she picks cases that make great TV, but she often deals with sleeping issues and you might be able to find some advice there that will help you out. I really hope this helps! You must be so exhausted. Good luck.