Do you have to go back to work at all? If not, I don't see how your baby will be too attached to the domestic helper unless you leave everything to her.
I have to work, during work days my mum takes care of the baby for about 4 hours and the baby is alone with the DH for about 5 hours. As soon as I get back home I take care of the baby (bathing etc.)and if it a work night my mum takes the baby at night. During weekends my husband and I take care of the baby.
We have had no problems. The baby recognises me and my mum and has not shown any particular special attachment to the DH. Although must say baby is only 5.5 months.
But I also had your husband's concern and have therefore decided that I will only keep the same DH for two years so my child will hopefully not be too attached to any one DH.