My wife lives and works in California, I am retired and live in South Dakota. At times I will stay with my wife in California and she will stay with me in South Dakota. I do not wish to give up my residence in South Dakota and her work keeps her in California. Is it legal for us to have different states of legal residents?

You are free to live where ever you wish, my wife's parents have keep separate households for 20 years.

... Is it legal for us to have different states of legal residents?

Yes. One spouse is not required to have the same state of residence as the other.

Thank you for your answer. This I'm getting old and paranoid. Thanks Again.

Thank you for your answer. With all the regulations these days I guess I was a bit gun shy.