Literally killing me

My bf and i are long distance at the time due to college. We see each other monthly and have a great relationship. He has a much more active social life compared to me(pre med so i study a lot) hes in a fraternity and they often have date parties. It literally kills me that i can't go with my bf (9 hour drive) and it kills me when he says he wont go or ask someone else because i want him to have fun. I know he wouldnt cheat or anything so i don't mind him brining a girl friend since everyone else has theres there. I just don't know what to do.