relationship problem

Please help i have no idea what to do. My bf and i are long distance and just saw each other for the first time in 2 months. This is our longest break since we usually see each other monthly. I honestly cant even begin to explain how i felt last night. I started dating him cause of his kind and sweeet personality. I felt like I was on a date with a raging alcoholic and sex obessed guy. We are only 19 and begin together a year and a half. We were so similar when we started dating. He knows im waiting until marriage for sex and i have a glass of wine maybe twice a month tops. All he was doinf last night was texting his friends about getting drunk. Also all i kept hearing about were girls. Hes never been like this before i love him so much but was ready to walk out of the restaurant. I understand people grow apart and all but you dont act like to who you are dating. Everytime i bring breaking up he falls apart crying. What do i do? How do i even tell him how i feel without being nasty? Im just so upset and at a loss of words right now. Thank you!