Sweat from your armpits and groin smell, because it contains fat and other salts that emit odor.
I still haven't seen the study that confirms your assertion that fat people have better sex. Adonis would have posted 10 by now.
If it smells, it smells on all, fat or not. There's no argument there.
You have allready showed your worried about your body, worried that you won't see your dick etc. you are the typical brain washed stereotype male - insecure, worried, afraid and ashamed.
Of course this affects your sex life.
A fat guy that is fine with who he is, who enjoys life and life it to the fullest - and the fattest. Doesn't have this problem. And he has a great sex life.