I'd be surprised, then totally and completely pissed - what, you can fuck a guy for money but you don't want to fuck me? - and then, I'd do what a lot of husbands do: Just say, "Okay, honey, whatever makes you happy..."
Well, you know what they say. An unpleasant job is a lot less unpleasant if you get paid for it (or if you have enjoyable co-workers.)
And what is your opinion? Years ago, my girlfriend stripped on amateur night and entered bikini contests. So, a couple approached her about doing a live sex show at an upper-class private club. She was willing but feared someone might recognize her. If we had it to do over, she could have worn a wig and changed her looks.
Both have to buy in or might cause a problem. In time, this maybe happening. Hope you both come to an agreement.
Once they get it in their mind they want to do porn, it is hard to stop them. A friend of mine was approached about doing porn years ago. She almost did it, but decided not to. A few years ago she started doing cam shows. When she first started, I watched a few of her shows. She has absolutely no inhibitions.
Hollywood movies have a bunch of low life people. I would hate to see what porn might have. She needs to be sure that is what she wants, and won't regret later.
If she wants to do porn then help her achieve her goal. You can either be in it or be the camera operator while she is fucked by another man. There's a lot of husband filming wife porn out there. Some couples have made a shitload of money doing it. Sandra Offerson aka Wifey comes to mind. She's a buxom middle aged blond MILF who fucks guys while husband films. There's a shitload of their teasers on porn sites. Once they get a hook they sell the full movie.
The site my friend was on required all of the air performers to be registered. Neither her husband nor I could be on the other side of the camera without being registered with the site. That puts the damper on a lot of guys being filmed with her. There is no anonymity.