If I may add a new pshat you guys made me think more on the drush side: the pasuk reads “vsimach es ishto” and continues “Asher lakach” which simply means and he should make happy the wife that he took.
Or you may say Asher lakach refers to the fact that he took her, so he shall make her happy with the fact that he’s the one who married her, by being a good husband she will be happy that he married her.