Here you go with that "funky smell" narrative again LOL, something I've never noticed on either side and also something I've never seen mentioned until I came across a post of yours in another thread. You probably came across some smelly ones, and assumed they are all the same.
Regarding cheating, if you choose a bar girl, sex is business and they need to be paid. Why would you expect a girl with extensive sexual experience to be faithful? You're being compared with dozens or maybe hundreds of other men. That would include younger studs that older expats could not match. There's a very good chance you're boring by comparison. You might be smelly yourself. It's far more likely a sweaty expat is smelly than the girls.
If you choose a non-bargirl who hasn't been around you shouldn't have a problem, as long as they are with you for love and not money. I've never had a problem with Thai girls or Filipinas cheating on me. I'm talking about serious partners here.