The antagonist.
He's the main character. If he was the antagonist, he would be opposing the main character or causing problems to it.
internal conflict between two opposing desires
Opposing forces in literature refer to the conflicts or tensions that drive the plot forward by creating obstacles for the characters to overcome. These forces can manifest as internal struggles within a character, such as desires or beliefs that are in conflict, or external conflicts between characters or society. The resolution of these opposing forces often leads to character development and drives the story towards its conclusion.
. . . protagonist .
a struggle between a character and opposing forces such as other characters, nature, or society.
Conflict refers to a disagreement or clash between individuals or groups due to incompatible goals, beliefs, values, or interests. It can manifest in various ways, such as verbal arguments, physical altercations, or emotional tension. Resolving conflicts often involves communication, compromise, and understanding to reach a mutually beneficial solution.
The two opposing philosophies do not amalgamate with each other
"We were surrounded by the opposing army." or "To surround yourself with friends with good character is a wise idea"
This internal conflict leads to tension and complexity in the character, as they struggle to navigate their conflicting desires, beliefs, or responsibilities. It can create a compelling narrative as the character's inner turmoil drives their decisions and actions.
She is opposing the new policy because she believes it will have negative consequences.
The antagonist character is like the opposing force that goes against the protagonist. For example in Cinderella, the antagonists would be the sisters. The antagonist doesn't necessarily need to be the "bad character" but more of a person, idea, or force that makes the protagonists life, journey, or experience harder. Hope this helps!