Fighting happens because there is a clash between you and your partner.
You have two will powers and two desires.
The fight is the battle between two different energy realities.
The words and the visible aspects of conflicts are only a small part of this battle. Inside, another battle is going which is a psychic battle. This is the real conflict. That's where tensions originate.
Your mind is a territory.
When it gets invaded, you fight back to protect it.
Any form of irritation or tension is the result of an invasion of your mind by external energies.
Imagine having your partner playing loud music. It can irritate you because it impacts on your mind and invades your mind space. The result? Tensions build up, you get angry and attack to protect your mind space.
It is natural. It is an instinctual response.
When you fight, your two energies clash. They compete with each other for power and space.
Tensions rise because a part of you is attacking or being attacked by your partner.