5 year old - sleeping habits

Hi,

In the heat of the moment...

My 5 year old sometimes has problems sleeping through the night. She
complains she just wants her mother and that she is scared. However,
when her mom is working nights, shes fine and doesn't give me any
problems.

My wife is home more often than not and this leads to many nights where
my daughter just wont sleep through the night. Usually I'm the one
putting her back to bed. Its driving me nuts and there have been a few
nights when I don't get any sleep.

I don't reward the behaviour by letting her go to her mom *ever*, I
always put her back into bed but tonight I additionally told her every
time she gets up, I'm going to take away a toy. So she got up, and so I
did. And she got up again, so I did again. I feel really bad for doing
this. I dont know whats causing her behaviour and whether I'm punishing
her for something *I'm* doing wrong :(

What can i do?

TIA

.