I think we just have to get comfortable with feeling uncomfortable. Too often (altho' not necessarily in this case), women don't want to offend, even when they're being belittled or insulted.

Other times, we're too gob-smacked to say anything; a common reaction not just to physical assault, is to freeze in the moment.

We need to have a few phrases up our sleeves, and whip them out more ruthlessly.

Eg.

Him - “I wouldn’t bother. Save your money, mate, and spend it on something else."

You - "No, I'm good, I'll just spend it with someone else. Bye."

Him - " “Actually, I suspect my guess is rather better,”

You - "Yes, I suspected you would."

Him - “You’ve been watching too much Grand Designs!"

You - "And you need to watch more."

Doesn't have to be the wittiest comment, but we need to push back instead of berating ourselves or seething later.