Assuming your Wife can qualify for Chapter 7, she may certainly do so. The only way your credit will be affected is you apply for joint credit or if your Wife has joint accounts she must include in her bankruptcy. Hope this perspective helps!
Your wife's bankruptcy should not effect your credit. You already have a bankruptcy on your credit. Make sure you are paying all your bills on time to improve your credit and make sure you monitor your credit reports.
Your wife filing bankruptcy should not have any affect on you credit because you do not have joint debts. She will have to list all community assets in the bankruptcy and when listing income in her case, she will need to disclose all household income, including your income. Both incomes will be used on the means test in the chapter 7 bankruptcy. The court will look at the total household income, even though you are not filing. They will also look at the total household expenses, which will include your expenses. But, to answer your direct question, your credit will be fine if she files.