ironically they usually end it

as far as why they come back....
well

in my experience women tend to be a bit impulsive
and I'm 'inconsistent' ...a very bad trait to have

so when you have impulsive person A dealin with inconsistent person B

person A blows it up .... then person A may realize, although he had his shit with him, dude was very good to me and a overall cool person

after all the emotional bs, it usually leads to being cordial...to then being cool/friends/acquaintances