It sounds like you fell into a situation a lot of people do - you lose yourself in the relationship you are in. Of course your ex likes you now, as you are back to being the person that he fell in love with in the first place. However, that doesn't mean that he is sure that you won't change again if you get back together. And that is probably what is holding him up.
I would suggest that you stop sleeping with him until you get back together. There is no need for him to really make up his mind while you are still giving him sex.
And I agree with BackUp that you should not limit yourself and start seeing others as well. Not even to show your ex what he is missing, but because you are free to do so and maybe you will find someone you like even more.
Good luck.
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