@Sugar011,
I'm really happy that you have moved on and realised you are someone and deserve to be treated with respect...
You know, I think, when someone leaves you, "regardless" of how the person treated you, the closure isn't the same if you don't know why they left and you always wonder. Given how he was controlling and abusive and made you feel worthless, this would have been the final blow for you... I think, that's why you let him back in, to ascertain if you were still good enough, if he would kiss you and then you woke up:)
It's a normal emotion he controlled you for so long... What you need to remember now is, any time he calls, it's because he wants to win, like he always did and like he did then... That's all it is... You're better than that and you've got a chance to be loved...now... change your phone number.
I don't think you should feel guilty rather in the understanding of why that all occured and learn from it and let it go... I also don't think you should tell your now boyfriend, it was only a kiss and with a logical reason behind it, based on your history... Just learn from it and let it go....