She said oh I'm just going to bend over and let some guy fuck me to make my husband happy, great.
That statement there is very indicative. And it also means that she is not happy with your perspective.
Your talks seem to be quickly happening. Are you raising the issue or is she? And if she is raising it, is she doing so with curious questions or with an angrier or accusatory tone?
If it is the latter: You are much better off letting the topic go and reassuring her of your intentions and nothing more. Pushing to convince just becomes Pushing. And not everyone will be receptive of the idea. I know... I know... If you read certain things on the Internet, they promise that your wife will give objections that you can easily resolve and then she will happily go along with your fantasy.
But... This is real life. Reading on the internet will also tell you that Aliens are controlling our government and the world is flat.
Listen to **her** not the web.
And if *you* are bringing it up - then you are not putting her first, at all. You are putting *you* first. IF you are bringing it up again already, then you are not thinking of her pleasure or what she deserves, but about What You Want.
Your points about cheating are valid. They are also just as valid if she draws the line in a different place than you do.
It's just a fantasy, man. And often, fantasies do not line up with reality. Sometimes they do... Sometimes they don't... but what is your risk factor here for Just a Fantasy?
I think you really need to hear her out; listen to her and how she feels. It may not be what you want to hear or maybe it will - but what matters most is you are Getting To Know the real her. And that can mean a Lot.
A lot of guys on here would love to know their wife is playing around.
But a lot of guys in the world would love to know that their wife *actually is faithful* without deception or pulling the wool over their eyes. You might be looking a gift horse in the mouth.