Intimacy and Crohn's Disease

My boyfriend has Crohn's disease - similar to IBS. So far, sex has been rather painful for him; he hasn't been able to find a good angle to please either of us, and moving his pelvis hurts a majority of the time. Neither of us are really into oral, and we're trying to find other solutions for sexual intercourse. We'd prefer traditional penetration, but we're not sure how to make it work. Has anyone been in a situation like this, or have any suggestions/ alternatives we could attempt?