Help!! My new boyfriend has a small penis!!

I have a new boyfriend, I'll call him "Brian", Who I started dating recently. Before we got together, we'd been friends for 8(ish) years. Well, after being friends for so long, I figured I could forgo my "must date for two months before sex rule" and we sex sex. The problem is that he's really small. We are both on the heavy side, so a lot of the positions I've seen in porn won't work (I'm also physically disabled and have problems twisting myself into a pretzel for sexual purposes).

What should I do? We are still at the beginning of our relationship so we could probably back track to our pre-dating state. It would seem petty to do that just because he doesn't satisfy me sexually. I just don't know what to do.