Some people find knitting annoying and stressful (hard to imagine, isn't it?), so keep an open mind that your DH may or may not find knitting as relaxing as you do. My dad used to play solitaire (back when you used real playing cards) for hours, or would make stuff in his workshop (he had a lathe, so he made my mom dozens and dozens of lace bobbins) for stress release. Now he writes poetry. Some people like to work out. Some people like to garden. There are also some guided meditation CDs which (if he's open to that sort of thing) might be helpful. No DH, so I can't share stories of teaching him to knit.