There's a reason that your ex is your ex. This isn't true in every single situation, but most of the time it's better to stay exes. You have your whole life of dating ahead of you. Maybe being stuck in a rut with one guy for too long is really going to damage and break you. Whoever you are, you are so beautiful that settling just isn 't an option for you.
This post is particularly for a few friends of mine, but it does apply to everyone. Take it from someone who knows, going back to someone who left, cheated, made your life hell, or you had a good reason to break up with is always a bad idea. If they've done it once, they sure as hell will do it again.
You are better than that. You always were, and you always will be. Don't. Settle.
I am personally not dating right now at all, but I think the most helpful thing to do in a situation like this is to take a break from dating, to evaluate what you truly want and need, be constructive, and raise your standards. Being single can be the most glorious thing ever, don't look at it as a bad thing.