T.P.
well you have a 7 month old new child and a new marriage.
were you and you husband together/living together for a long period before getting married? maybe it is taking your daughter time to adjust. with a new child in the house and (i'm assuming here that you two haven't been together since she was born/or a year) a new dad/man in her life it's a big adjustment.
she's also getting more verbal at this age and have you asked her if she knows what 'not like' someone means?
my son who will be 4 in january says things sometimes and i'll ask him if he knows what it means and he doesn't. he's just heard someone else say it.
maybe she is taking his disciplin as him not liking her.which could be age appropriate in it's logic.
have you talked to her pediatrician about this yet? sometimes they can give you material on behavior at this age or suggest where you might find some answers with a different type of dr or other material.
i wish you luck. i have two three year olds (now till jan 24th when my son will turn4) and 3 can be fun but tricky.