If she doesn't care about rewards, go about it in a round about way. Mention all the retail stores that have been hacked and how if she had swiped her debit card there, your bank account could be compromised. Instead of stealing the credit card company's money, hackers are stealing yours. I used to work at a bank and fraud claims can take weeks to resolve. During that time, the bank isn't crediting your account the money that you lost. If you didn't have any savings and you had a mortgage payment come up, what are you going to do then?
I know this thread has kind of died down but I have a question for the OP. Is your wife adverse to you using credit cards whenever you're out and about solo or does she just not want to play the Credit Card Rewards game herself?? And were you into all this credit chess before you hooked up with her?
So what's the current situation? I'm curious how it all worked out.
@Asilomar wrote:I know this thread has kind of died down but I have a question for the OP. Is your wife adverse to you using credit cards whenever you're out and about solo or does she just not want to play the Credit Card Rewards game herself?? And were you into all this credit chess before you hooked up with her?
So what's the current situation? I'm curious how it all worked out.
For my wife, it all comes down to a matter of being able to save as much money as possible and avoiding any debt whenever and wherever possible. IIRC, she only has 1 credit card, which she uses only very rarely; i.e., only in emergencies. She also has all of her debt paid off. Whereas, I have ~18 total cards, and ~$15k in debt that I dilgently working on paying off. OTOH, she is not making use of any credit card rewards programs that I am aware of, and for various reasons that aren't 100% crytal clear to me, she has little if any interest in using credit cards for rewards purposes.
As to the question on where things are now: well I have recently cut down heavily on unneeded monthly expenses and avoiding unecessary spending, thus saving a significant chunk of monthly dollars, and so my wife is now going a lot more easy on me with the use of the credit cards. For example, I cancelled my Netflix DVD susbscription (saves $13.99 a month), cancelled my YouTube Premium subscription (saves $11.99 a month), downgraded my Netflix Streaming account from UltraHD to just HD to save money, and stopped all cable OnDemand rentals (saving ~$50 a month). Also stopped virtually all eating out, with the sole exceptions of certain holidays and misc. special events, etc. All cards continue to be PIF, with the exception of some cards with active 0% promo offers, and others carrying small balances with go-to interest rates below 10%. So I am on relatively good terms atm, with my wife 
None of that actually answered my questions... BUT, I am glad to see that you've reached a good place with your new wife. I can certainly see why she'd be concerned about your credit card habits and compromise is never a bad thing! Best of luck to you!