Relationships are difficult. It's life. You love life, so you fight. You fight because you love. Otherwise, you wouldn't fight. You work. You don't want to die. Why life is a fight, I don't know, but gosh! It is.
As you know it is a comedy so everything is a little bit pushed. That's what's funny about this kind of movie is you can laugh about the absurdity, and the bad side of life.