Why is so painful for me?

me and my current boytoy had for the first tim ein october,im noy a virgin but it hurt so bad it even bled.he is roughly 7 1/2 inches and every time he went deep it felt like he was hitting somtheing and every time it was a very dull and painfull type of pain that made me flicnh and push him away.i reall want to have with him but its really painfull wahat position could i use to help the pain?does it have to do with how long my is?