Why So Hard?

So, this doesnt pertain to me, but its just something i have been wondering that pertains to a lot of other people. Why is love such a difficult thing? I cant say i havent done any of this before, but for one, why is it that when people see their relationships crumbling, they continue to try and make it work? All it does is hurt the people in the relationships, and it gets you now where. Second, why is it that when people break up becuase they arent working out and it was an unhealthy relationship to begin with, why is it that they want to get back together with the other? Usually it is only one or the other that wants this, not usually both from what i have experienced, but why do this to yourself? All it does is hurt you and it for sure doesnt help with getting over the person you just left. Thirdly, why is it that people give others hope by doing things they shouldnt even when they know that for sure they dont want to ever be with them again? Fourth, why is it that people think that doing sexual things with people will help ease the pain? It never ever does, so why do they still do it? And lastly, why get into a relationship that you know wont ever last or rush things to much so that the relationship ends as ubruptly as it started? These all just kinda make me wonder because all of the people that i know have done one of these and as i said before i have done a few as well. But why cant people just understand that doing these things never works? Will we ever learn?