Can his size stops us from different sex positions

I’m a very big girl and my man is thin and SMALL... we only do missionary which I like but I don’t get off from it like he does. We tried doggy once and idk it hurt and it wasnt my a-hole (lol) and sometimes he can’t find the whole which pisses me off. He’s 40 I’m 27... I want to ride him but I tried once and was completely uncomfortable and he once made a joke saying if I want kids don’t squish him... it was a horrible joke but he’s a complete gentlemen but I’m getting frustrated... any ideas or tips? Please and thank you