For much of the story we think Mr. Mallard is dead. He doesn't appear in person until the end, and even then we don't know that much about him. Instead, we learn more about Mr. Mallard from the reactions of other people to his supposed death. So, we know he leaves home to work, and that his work is far enough away that he needs to use a train (a train accident, supposedly, is how he dies). We don't know his profession, when he left on this journey, or how frequently he travels.
The behavior of his friend Richards, who rushes to the Mallards to comfort Mrs. Mallard after her husband's death, suggests the strength of the bond the two men had. Maybe Mr. Mallard was such a great friend to Richards that Richards has to immediately drop everything to come to the house and be consoling. (Or did Richards have another motive? See out thoughts on Richards for more on this.)
Given that this story is set in the nineteenth century and that Mrs. Mallard is home with a weak heart, we can presume that Mr. Mallard's work is paying for and supporting both of them. And what about Mrs. Mallard's sister Josephine? Does she live with the Mallards? Is Mr. Mallard supporting her too? If he is, that would suggest his generosity and/or kindness.
So what does Mrs. Mallard think of Mr. Mallard? Clearly, people in society expect her to be ruined by the news of his death and aren't surprised at all when she cries up a storm. We know that Mr. Mallard had "kind, tender hands" (13) and that throughout their married life he "had never looked save with love upon [his wife]" (13). Well, that seems like a pretty nice quality. Maybe it's a little unrealistic, but it's still nice. From that brief statement we can infer that Mr. Mallard was nothing but nice to his wife, and never did anything to make her feel like his death would be a blessing. But for all that, Mrs. Mallard is miserable as his wife. We don't know whether he has any idea about her unhappiness. We don't know him.
When Mr. Mallard comes home at the end of the story, he's "a little travel-stained, composedly carrying his grip-sack and umbrella" (21). That's it – that's really all we get. He's a composed guy. He'll never realize exactly what his wife went through when she thought he'd died. And, heck, maybe that's a good thing.