unrequiter
/ˌʌnˈriːwɪtər/Definitions
1. noun
One who fails or refuses to reciprocate affection or a romantic interest.
“After a year, she realized he was just a casual unrequiter, never intending to take their relationship to the next level.”
2. verb
To fail or refuse to reciprocate affection or a romantic interest.
“She felt unrequited by his lack of interest in her, and their relationship eventually ended.”