That should NEVER fly in a marriage.
What you SHOULD do is have one account where all of your INCOME goes, and then you both designate a certain amount of "blow money" each month that you can spend on anything you wish. This should be after all bills are paid and an agreed-upon amount of debt reduction is met (if you have any debt).
Again, YOU need to change your attitude. You have not been "taking care of her with my savings". Your WIFE has been supported with money that belongs to both of you.
You should have added her to the checking account. It should not be YOUR checking account. It should belong to both of you.
The problem you have now (though you should still pursue this) is that if you tell her she can have a joint account with you, she will think it's ONLY because you want access to her money.
I am dead serious about this, have her read this thread. Have her read this next part especially.
1) Have ONE checking account and perhaps ONE savings account that you both have equal access to and equal ownership of.
2) All money that you don't have invested in retirement accounts needs to be there.
3) She needs to deposit her windfall into one or split up into both of those accounts.
4) The two of you need to decide how to spend the money you have. Ideally, bills should get paid, and debt reduced and eventually eradicated, but the two of you TOGETHER get to decide the best way to do those things.
5) Buying things for the family needs to be a decision you BOTH agree on. It is NICE that she wants to pay off your car, but that is a decision that BOTH of you need to make. She doesn't get to have the power over this money and wield her whim upon you, just as you don't get to do the same thing because you make money and she seemingly doesn't. You are a married couple, a team.
6) It is VALID and FAIR that she wants to have money to spend on herself, EVEN IF she isn't making any income. BOTH of you get to do that. I just bought some guitar strings online, and I told my wife I did so AFTER I purchased them. She makes similarly small purchases and then tells me later. We discuss anything even remotely big before we buy. This is called "blow money". Unless you are in desperate financial straights, you both get to have this, EVEN IF ONE OF YOU ISN'T WORKING. Things that fall into this category are typically things like Starbucks, a reasonable amount of money spent on clothes and accessories, stuff for the car that you want but don't need, beer/poker night (don't go crazy) with the fellas, etc.
I'm not naïve. I realize that especially people who get married later in life and/or are in a marriage that is not their first one, that there is some extra possession of material things that isn't there for people who were married younger and in a first marriage. I understand the need to want to protect oneself in that way. That doesn't make it the right way or the best way to go about it though.
Good luck.