Leos are a proud sign and will not admit when they are wrong. They will not beg you to stay and will easily let you go. Later, they might have their breakdown but will not show any signs of weakness in the moment. A Leo might give you loads of rather blunt relationship advice on how you should or shouldn't be. Breaking up with a Leo takes some preparation and research.
Begin to appear scruffy. Let yourself go and look unattractive. A Leo likes to have someone nice looking on his arm, someone who takes care of themselves. Begin to look like a bum and he will be out of the relationship.
Become boring and unsocial. A Leo loves to wine and dine with friends. They love meeting new people and doing all sorts of activities. If you refuse to do any of this with her, she will lose interest in the relationship quickly.
Stay at home and eat junk food. Leos pride themselves on their appearance. It is all about the hair, the wealth and his fashion sense. Become a homebody and eat fast food and you will be out the door.
Tell him that he is wrong. A Leo will do everything he can to prove he is right. He will even make up evidence to back what he is saying, or pull out past mistakes you have made. Tell him you think he is wrong and he will say 'adios!'
Act poor and stingy. Leos love the finer things in life and love a nice meal, champagne and limos. Act like you can only afford a meal at Denny's or the nearest diner, and she will eventually distance herself. Possibly to another city.