Meleager in The Story of Atalanta
Meleager is pretty much the only dude who's nice to Atalanta. You've got to give it to him for standing up to the rest of the dudes on the Calydonian Boar Hunt. When they don't want Atalanta to go on the hunt because she's a woman, Meleager says, "No way. This chick is an awesome hunter, and she's coming."
When Meleager's uncles try to take the hide that Atalanta rightfully earned by hitting the boar first with her spear, Meleager killed them for the offense. (A little much, but alright.) Althaea, Meleager's mom, is so ticked that he kills his uncles that she kills him by throwing a magic log on a fire. So, in a way you could say that Meleager gives up his life to stand up for Atalanta. (Oh, how noble.)
Before you go thinking that Meleager is just a super nice guy or something, we should point out that he may have ulterior motives. Namely that (even though he's married) he totally has the hots for Atalanta. In some versions of the story, Atalanta is super into him as well, but they can't get together because she's taken a vow of chastity. According to some, Meleager was an Argonaut along with Atalanta, and their unrequited love plagued them both for the entire voyage. (Hot.)