Tmi* Sex Positions

I'm chunky.

Im not a big fan of being on top during sex. For me, missionary is just sexy and simple, along with the few others we can actually do.

My boyfriend hates being on top, bc it "tires him out," but we have sex right before bed anyway.

Many of the positions we've tried dont work, because my thighs are too big or because our bodies are nowhere near the same length/size.

I just simply dont enjoy being on top most of the time. What can we do?