Have you ever gotten the feeling that you don't really like your SO? Did you get over it? How?

I don’t like my wife very much these days. I try, but she’s always unhappy about something. She is occupied with work, kids and stuff, but she’s unhappy. We’ve been married 15 years, have two kids, and I’m at a loss. I’ve tried to get her out of this funk, but truth be told, I don’t know that I will ever like her again.