Sex sex sex i really need help!?

Ok me and my boyfriend have been dating for 6 months and he the topic of sex has been coming up alot but im terrified of having sex cause im 15 and there isnt any way in hell im risking getting pregent,so i want to wait till marrige but he wants to lose his before he get out of high school. his exact words were "i want to have experience before college" that got me mad,but most of the time he comes over my house and i have a big family and he always tries doing stuff over there and i hate it cause i dont want anyone to walk in. And we never go over his house so it makes it impossible to do anything and he gets mad when i dont want to do stuff over my house. we get into eny fights over stuff like this and its really annoying i dont take our fights to serious cause there dumb, but i wonder if hes just using me as practice before college! what should i do?