Judging from how sore I am today after last nights marathon....legs, abs, arms...I'd have to say I count it as a workout. I certainly don't feel like this after a vigorous walk lol. Now a quickie or if you just lay there, I wouldn't count that. Guess it depends on the amount of time and how actively you participate ;-)
i read a study saying the average couple has sex for 9min, and the average amount of calories burned from sex is 40. Now if you and hubby are very active, changing positions, doing it all over the place, and have sex for more than 1hr, then yea that would be an exercise session to me. But the standard 9min/40calories...No, you'd burn more calories if you walked up and down some steps for 9min.