you're the best - but just not mine

I donno what is good and what is bad anymore
when you called today, all my sadness was gone
you took away every single worry that I had for a long time
I donno how long I will stay in this euphoria
but you did it for me
and you were great
you were just what I needed
all that I ever needed
and yet you are not mine
you are someone else's

so who is good for me?
some one like you that is the best thing ever and makes me feel myself again?
or someone like him?
that is keeping me in the unreal state of unknown, scared of tomorrow, and scared of myself...
who is better?
I think I know..........................