There are several possible reasons. Can you give us some information on what her routine looks like, in particular
a) walks - frequency, length
b) when she is left alone in the house - frequency, length
c) playtime, toys in the house, mental stimulation - what does she have?
d) if she has always destroyed things, or if this is a recent change, and if so whether or not anything changed around the same time
e) if there's any pattern to her behaviour - for instance, does she destroy things when she's left in the house alone?
f) anything else you think might be relevant
You may need to speak to your boyfriend to get answers to these, but the answers will mean that people can provide some helpful information. Any solutions are, however, going to involve work - there are no magic wands in dog training.
You should, of course, remember that we're unqualified strangers from the Internet! If you'd like us to redirect you to someone who's well qualified, local, and can come and do a proper consultation, let us know.
Someone else will be able to give you appropriate information on introducing a dog and a baby (I've never done it) but it's good you're thinking about it now as it means you can prepare the dog - one example would be playing tracks of babies crying, quietly at first, and then turning up the volume over time to a more realistic level!