The romance with each love interest loosely follows a different romantic trope. Charlotte's romance follows a 'fated lovers' or 'destined love' trope, meaning she and the MC are 'meant to be together,' and their characters and backstories reflect that. However, you are not forced into a relationship with her.
In contrast, Emma and the MC follow a 'forbidden love' trope - they are definitely not meant to be together, but they can still pursue a romance.
Each romance is unique and offers something different. I didn’t mean to imply that one is more important than the others.