We never get to see Simba and Nala kiss. Disney has made animal couples that kiss for years. Even Kovu and Kiara get to kiss although accidentally.Do you think that is because they just don't and never kiss as a couple?
Well Nala kissed him during the "Can you feel the love tonight" song it was probably all they could do because since it's a Disney movie and they're animals so doing too much of it would of made it awkward is my guess :P