I came across a question which is "I don't know why am scared to lose you when you are not even mine", so this made me start thinking of how possible it is to lose someone that was never mine.
Finding answer to this question became difficult to me until a friend replied to the same question saying "The fact that you know the person is not yours, why are you scared to lose the person". Her reply made me ask her if she has been in a situation whereby she is in love with a guy who has a girlfriend(not her) and she replied YES but the only thing is that she sit herself down and talk to herself to let go and stop whatever she is feeling because it can't work then I asked her how she felt when the guy stop giving her the attention she was getting before, she replied saying she felt bad, that the space actually came from her, even though the guy came back but by then she is out of whatever she felt for the guy.
Well that is her, some other people would have been so attached to the person and they will be afraid to lose someone who was never theirs. To some people viewing that situation it might be a lack of discipline and untruthfulness to oneself which is true but some people like to live in a fantasy world that they them self know can never be real. It's okay to fantasize (everybody do) but we should not forget our self in the fantasy world.
Some people can be so obsessed with their fantasy that they do anything to make it a reality, that is why we keep seeing people doing things we find hard to understand when they explain or they don't even have an explanation for their action because they wake up to reality after they have done the damage to make their fantasy come to reality.
It is not wise to get lost in a fantasy world and discipline is required to achieve that. We don't have to do everything because we think we can and there are some things we deliberately have to stay away from so we won't get hurt at the end.