Are you suggesting that spouses of Congressmen shouldn't be permitted to sit on corporate boards? (And presumably, should be excluded from any of a range of careers in the private sector.)
No, I'm just claiming policy makers can be influenced by corporate boardrooms. I don't really have a solution for it, and I can't really say that I know whether or not this is a big problem that needs solving, but is there legal ways for companies to use board positions to affect policy makers? Yes.
Personally, I don't think it's the worst. I would rather they had to do this than get huge retirement packages as they do in my country after their service. Also, if their spouses can make a living being involved in business so politicians can't use sympathy for their poor family as leverage to get higher compensation that would be good too. But we can't handwave the issue of corporate influence over politicians however we choose to deal with this.