Fear of committing kufr

Q: I am getting married and I am worried about Imaan and kufr. Since I heard that nikah will be nullified if one of the two did kufr, what precautions should one take?

Is it kufr to like kuffaar daily life ways? E.g. If someone wears kuffar clothes like pants and shirt, if we praise that person by saying that they are looking pretty in this dress, so is this kufr? There are many kuffaar thing which people have adopted nowadays and my husband to be is a duniyadar. Please guide.