I don't think the date is important - after all i doubt Dean was able to count days down there. it's just kinda figure of speach - to let us know that he held up as much as he can and then gave up. I don't see any non-con reason in partucular for breaking Dean i think it was more like all the tortures that at some point became unbearable. He just can't take them anymore he was irrational and was ready to do everything to stop - i don't even think he'd understand what he was suppose to do he knew only that saying Yes he'll stop the pain.

is the fact that fanfic never considered that Dean could be broken, that he would make the choice he did as presented in canon
That's why fanfics are fanfics and Kripke has profi writers in his crew. The fact the hell broke Dean doesn't make Dean less hero than he is. But i think some ficwriters were afraid of showing Dean broken... but that's the point of being afraid of hell - hell can break everyone. It's only a matter of time.