Loosing your virginity

I've tried four times to lose my virginity to my boyfriend but everytime the pain is unbearable ( I'm usually fine with pain like I've had my shoulder dislocated and put back into place and accidentally cut my foot to the bone) I've never had this much pain before. He is really big and thick ( I've done other stuff with quite a few guys and he's the biggest I've seen ) but I don't understand what is wrong with me ? Any advice or help ? Anyone had the same problem ? ( fingering hasn't helped btw )