Please don't get this wrong, I am not trying to influence you, I just tend to blurt out where I feel the story could go and would feel natural to me in regard to what I know already.

This here feels like they both need to be unhappy for a while (Harry because he used Draco for sex and tried to manipulate him into a relationship, Draco because he has not accepted his sexuality yet, and yes also used Harry for physical release) and do some serious growing up, before they can get together.

And we should not forget that because they are in 8th year, they are both regarded as grown ups in the wizarding world, when Narcissa feels the need to order her son about.