That quote is pretty messed up.

Indeed. Who lets their girlfriend have another boyfriend?

she's my girlfriend, not my property, she can do what she wants

The flaw in this delightful analogy is that boyfriends don't typically sell their girlfriends to each other.

And that women don't get "used up" because they have sex! Truly delightfully disgusting, that analogy. You'd probably need to own a Ferrari to come up with such nonsense.

A shocking number of people believe otherwise. I heard even more disgusting analogies about this, but one is enough for today.

That isn't a flaw at all. There was no mention of selling; it could be referring to a car being passed down from generation to generation.

Speak for yourself