It depends on the situation, do you live with the person, is there any chance, ever. It is ok to ask if you ever stand a chance with them, if you don't you might always wait on them. I love a friend of mine, but we can never be together because we are always with other people. That does not change my feelings for her, but I know it will not work. My current girlfriend knows I love this other person but I told her I would not leave her for her, that would be unfair. You just need to let the other person know how you feel, and if they say it will never work, still keep those emotions, but you have to move on and find love somewhere else. You don't want to be alone forever, I know I don't. But find someone else you can care about.