Hilariously, my 35 year old EX bf just did the same. I guess some guys never grow up. (find one who treats you well....my only advice. Don't settle for someone who hurts you).
Boys in their late teens have very fragile egos. If you fight mean, (assault his intelligence and manhood) then it is quite likely over. If it was a fair fighting, (respecting what he said and offering your feelings and view in a respectful way) and you proved him wrong on some point, he will probably lick his wounds and come back. <br />
No matter what your age, if you want your relationships to survive and thrive, you have to learn to fight fair when there is a disagreement. <br />
Yes. For the 479th time.