Male perspective
I'm just going to put myself in David's shoes for a second
And I feel that he was, as
>>2 said, very hurt and confused when you broke up with him. He was also probably feeling very hurt, since you only said to him that you couldn't be with him when you were thinking of someone else...
Such a statement can destroy us guys, and it probably destroyed him as well.
But one thing I want to say is... I doubt he will come to ask you why you did that.. um what I say may be harsh, but he may be way too angry/hurt by you to think deeply enough to come after you to find out.