You deserve someone who gives you all there is to give. Someone who cherishes you with every breath he/she takes. One that has eyes only for you, one who's with you for the long haul and not some loser who just wants to smash and dash. You deserve a guy/girl who wouldn't dream of a life without you, one who just the mere thought of losing you actually brings them physical pain. We all have a fear of being alone at one point or another but it shouldn't be the reason why you stay in a relationship that clearly to you isn't working. I personally believe that everyone has that one person that they're meant to be with and you'll eventually end up together, call it fate or whatever but I think it's real.
You deserve so much more if only you believe it. :)