While many posters are advising the OP to watch what goes on with regard to the new partner being controlling, there is absolutely NOTHING you can do about it, should that be the case, as I have learned to my horror. When our children fall in love, whether it be with a good person or bad, it is THEIR choice, and theirs ONLY!! We can no longer influence them, as they believe themselves to be in love with the new person, and it is them, and only them, who will have any influence, until the weaker partner realises what is going on, and asks for help.
My advice OP, would be to do exactly as your daughter asks, and however much you may disapprove of her new partner, do NOT rock the boat, or you will very swiftly find yourself out of the picture, and with no contact with your daughter or grandchild.