Sex help?

My boyfriend is a pretty big guy with a relatively small penis for his size. It doesn't bother me since we stick to positions that work for what we both desire, like missionary and positions with my legs over his shoulders for better penetration. I'm 16 weeks pregnant now, though, and these already are becoming uncomfortable. But normal pregnancy recommended positions like spooning ones or doggy style don't work because he can't get in. Does anyone have any ideas?