See, as long as the person you're waiting for feels your love, it's alright to wait. It's quite OK to wait for her if she is asking for minimal time to focus on her career. If she has asked you to wait for her and you are confident that she truly wants you in her life, then do so. If you know she likes you but you both feel the moment isn't right, although you believe she will be with you in the future, then yeah, wait for her.
However, waiting for someone who has cheated on you is unwise. If she has left you for someone else, don't wait for her. Don't wait for her because even if she returns to your life tomorrow, there's no assurance she won't abandon you again. If someone can cheat on you once, there's a good probability that they'll do it again.