I thought people with ADHD were supposed to be hyperactive!

My husband is inert. I feel like I'm married to a potted plant. When he comes home, he's "tired." He used to like to cook, now it's "I'm too tired, will you cook dinner?", which of course, I don't mind since I'm not working. Then we curl up in bed to watch TV (bedroom is the only room we can afford to heat), I knit or cross-stitch and he falls asleep. He says there's nothing wrong but it's driving me nuts. I thought they were supposed to by HYPERactive, not HYPOactive! Does anyone have any ideas?