The "C.H.I.P.S." actor recently revealed he had relapsed after 16 years of sobriety so, since then, he's ordered a number of tests to keep in their home in case his wife feels "nervous" so they can be upfront with one another.
Kristen told Self magazine, "(He said), 'You can drug-test me whenever you want. I'm going to buy some tests. I'm going to have them in the house. If you ever feel nervous, I want you to have access to this and I'll do it, no questions asked.' "
So far, the 40-year-old star hasn't asked her spouse to take a test and is content with the fact he just doing his best to stay sober once again.
The "Frozen" star added, "He's just good at trying, and that's all you can ask of anyone. No one's perfect. He's proven to me that he is committed to evolving and he loves personal growth."
Meanwhile, Dax Shepard previously admitted he was initially terrified to go public with his relapse.
"I had all kinds of bizarre fears, like, I have sponsors on my show, is that something that could cost me money...," he explained. "But the number one thing I was afraid to lose was... I get so much esteem out of being someone who's vocally sober and I have people who write me, 'I'm month one', or 'I'm week two', and I love that. That's my favourite thing about being in public, so I was just terrified I would lose that. I really cherish that."