Masha is the daughter of Shamrayev and Paulina. She's dramatic and depressive and she always wears black. A moody type—think goth—Masha's attracted to Konstantin's Edgar Allan Poe act:
"You should see him whenever he recites something he wrote: his eyes burn, his face gets very pale and intense. He has such a beautiful, sad voice! You can tell he's a real poet." (1.19)
But recognizing the futility of her love, she tries to get over it. To help, she drinks: "Women drink a lot more than you think," she tells Trigorin. "Some of them are open about it, like me; most of them do it in secret" (3.9). She also takes snuff, "a disgusting habit," according to Dorn (1.182).
And, finally, she marries another man in the hopes of a cure. But Masha still hangs around the house reading Konstantin's works and dancing when he plays some melancholy serenade on the piano. Far from canceling out her love, Masha's marriage to Medvedenko only makes her life more unpleasant. She has a baby she clearly doesn't want, and can barely stand to be in the same room as her husband. Masha keeps on moving, though, sure she can outrun her love: "As soon as Semyon gets his new job, we'll move, and in a month I'll have forgotten him. None of this means a thing" (4.33).
Keep telling yourself that, Masha.