And no, all is NOT fair in love and war. It is NOT okay to say or do what you want and then come back from it afterwards and act like nothing happened.
If you want people to treat you with respect and you want your arguments to go smoother, then offer the same respect you would like to receive.
If you love the person in front of you, then remember that this argument is part of your relationship of love – you still act with love in a relationship.