Good advice on the "don't stretch it"! Keep that firmly in mind because you will want to pull it the way you would non-elastic yarn. Don't do this!
It is a very tiny % elastic but that little bit does keep it nicely in shape as a sock. If you pull the elastic all the way out when you knit, then it has no where else to go when you pull the finished garmet on - does that make sense :??
My advice is to take some extra yarn (in a really wild color like green or purple that you would never use for socks for your DH ) and practice with it. You can just make a smallish tube and see how different tensions affect the tube and how much give you end up with. It doesn't take long to figure out the best tension for you but I would highly recommend playing with it before starting DH's socks. It took me a couple of swatches before I felt comfortable with it. Now I'm pretty sure I got it. I like working with it now as my DH is like yours - "socks should be made of cotton or linen!" - and it does work. NOT as nicely as, oh.... Tristan :happydance: but it does work.
Good luck and let me know how it works out for you. OH!!! Important!!! I used a size 5 needles and it was too loose - size 4 was better but 3 might even give better results. If you have them, try different sizes from a 4 down - don't use a 5 for socks!! NOT a good idea - you need garters to keep them up :oops: