wrong.
there isn't a sane woman on earth who will risk a great relationship just to get laid by someone different.
if she cheats on you, it's because she's missing "something" it can be emotional or physical. it's usually emotional.
you on the other can be in a great relationship (assuming you're a guy) and if a hot girl offers to blow you and there is zero risk of being caught, you'll let her suck your dick.
you can argue with dullboy, but you'll be wrong.