It's the lack of progression. you have reached the stage in a relationship where sexually there really isnt any further to go, and not that this is a bad thing, but after the first time a couple has sex, the kind of new relationship excitement really begins to fade fast. once they get into a pattern, or things are stagnant, girls begin to kind of expect things. the dynamic kind of changes. instead of waiting for the next step in the relationship, and the relationship becomes a little more platonic, even if you fuck just as much, if you stop doing things for them you regularly do it kind of disrupts the norm.
i dunno. these are just observations. lol i think i kinda repeated myself in there. oh well.