wistful
/ˈwɪstf(ə)l/Someone who is wistful is sad because they want something and know that they cannot have it. 依依不舍的
adjective [原级] （因求而不得）失意的，伤感的；思念的，怀旧的
I can't help feeling slightly wistful about the perks I'm giving up. 我对自己将放弃的外快不由感到有点依依不舍。
