*SPOILER ALERT! If you dont want to know what happens, stop reading!!*
In the season 3 episode "Clear", Rick, Carl and Michonne go back to Ricks hometown. They find Morgan (who has gone a little cuckoo but if i'd been through some of the stuff that he'd been through, i'd be a bit crazy too!) Hes living in a building that hes outfitted with A LOT of zombie boobie traps as well as boobie traps for humans as well. During the episode, he tells Rick that he couldnt bring himself to kill his wife and in the end, she ended up biting Duane who turned and Morgan had to kill him. So yes Morgan is still alive, no Duane is not.
As far as the graphic novel version of Morgan, you have to remember that the novels and the show are two VERY different things! Some of the characters that are still alive in the show are dead in the books and vice versa. If your curious about novel Morgan, heres a link:
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Sorry for the long responce but i hope it answered your question!