I have seen this in visual media, but not really in written media so I am sort of at a loss as to how to proceed.
I am writing a first person narrative where the main character is almost constantly in his own head. In fact some 75% to 90% of the narrative is in the narrator's head if it isn't dialogue. And the narrator thinks a lot during conversation. Example:
"So what are you thinking about?" she asked.
And there it was. The loaded question. It was the question she always asked me during any lull in conversation. It always made me super uncomfortable and she knew that. Oh gods she's looking at me. Quick think of an answer.
"I love you." I said.
Hopefully this is a decent example of the dialogue. The idea is that it is entirely first person driven. My question is: how can I convey a narrator that questions himself constantly in conversation without breaking the flow of the dialogue? Do I interject the internal monologue in the middle of the dialogue or is there some other method that I am not realizing?
Note: the internal monologues are a device to convey the narrator's character and mental inclinations so it would be hard to get away from them entirely in the writing.