K.-
I know how you feel about asking your husband to pick up after himself, especially when you want daddy to be a good example to your son.
But being negative and feeling as if your husband were another child simply won't help. Negativity feeds on itself, and the more you feed it, the more negative you'll feel.
Try this - give the "picking up" thing a rest for a month or two. Just stop mentioning it. Try saying as you clear the table or picking up his socks, "Here, honey let me get that for you. You work hard to support us." Now he may be a pig and say "That's right." Or he may be so shocked he may not say anything. But being positive and respectful to him won't hurt you, really. When you back off on the negative talk to him, he'll stop acting like what you do doesn't matter. I know, I went through almost the same thing.
And as for your son, he sees You, his Mom, working hard every day to take care of him, feed him and love him. He may want to "help" you with your chores. Let him push the button on the washing machine or the dishwasher. Teach him to fold socks and show him where to put his toys away. He's at the age where he still wants to help you and he's young enough to still learn from his mom.
Just try being respectful to your husband and accept the teaching position as yours for the time being. You may see a turnaround in your spouse. I did.
Good luck and God Bless!
B.