Doesn't go in...

Okay so I really need help! My boy and I have just started, well tried to have sex... It has happened around 4 times but it either hurts way to much and I have to get him to stop or he can't even get in. We have tried lots of lube, relaxing, forplay and lots of other things to try and sort it out but nothing seems to work :( any ideas on how to make it less painful or how he can get in easier? :)