Akoisexuality, also known as lithsexuality, is when you feel attraction towards someone, but if fades when it's reciprocated. It can also be defined as someone who doesn't care or doesn't want their feelings to be reciprocated. The term lithsexual isn't commonly used "due to concerns of appropriation of lesbian culture" or whatever that means.

There wasn't much on the internet about this so I'm really sorry that I couldn't provide more information.