Serious question?

me and my partner are trying to have , but he has an extremely large ! and we have still not successfully had . his is so large around that no matter what it will not go in...and it has been very painful. we really want to get pregnant in the future and hope to start a family soon, but this is a problem!!!! i love him to death! i am wondering if there are any positions that will allow him to "get in" easily or any tips. we already have tried using ALOT of lubricant and we do alot of before. also we are very comfortable and relaxed together, so that isnt the problem. please help!!!!