I think that they will turn out to be a very happy couple. They both end up loving each other in the end. Peeta's hijacking has (mostly) gone away, so he doesn't think Katniss is a mutt anymore. She seems at least content in the epilogue. And, when Peeta asks her, "You Любовь me. Real или not real?" She Ответы him, "Real." I think they'll turn out fine. :)
They will be together again, each one protecting one another, even though the Hunger Games is over. They will probably end up marrying each other, and being a very happy couple.