Where Do I Stand?

Almost the first thing you have to decide when you are starting to work on a story, is where the narrator stands in relation to the narrative.  It sounds complicated, but actually what it means is working out how the story will be told.  One option is to use the third person (he /she), relating events from the all-knowing point of view of the author, who sees with equal clarity into the heart of every single character -- this is the classic approach, and probably the most straightforward. Using the omniscient third person, you can eavesdrop on the most private thoughts of the hero and heroine and you don't have to explain how you know what is going on at any moment in any given situation - you just tell it like it is.  That is its great advantage; its main drawback is that forming an intimate, personal relationship with the central character can sometimes be hard to achieve.

This is why many writers opt for the first person narrative, where the story is told from the point of view of "I".  This creates the impression for the reader that they are actually inhabiting the psyche of the protagonist, getting under their skin, and it makes it much easier for them to bond.  The fiendish difficulty presented by this kind of storytelling is that the narrator - I - can only describe what he or she has  actually witnessed themselves -- everything else required for the development of the plot has to be overheard / reported / surmised, which has obvious limitations.

To explore which approach might be most comfortable for you, write a paragraph in the third person on the theme of, say, infidelity, then rewrite it in the first person, so that you can compare and contrast the challenges and benefits of each and see which works best for you and your story.