I do suggest that new words be created, or old words be repurposed, for new situations. I don’t think sanitizing “husband” and “wife” so that they lose their connotations and their relationship with each other is the right thing to do. To me, calling someone my “husband” implies that I am the “wife,” and there’s a whole lot of baggage involving sex roles and traditional marriage that those words carry with them. “Partner” seems to me to be a better reflection of the symmetric relationship between two men or two women. What gay men and lesbians have is not the same as what straight couples have, and I think we should celebrate the difference rather than pretend we’re just like straight people but for a few quirks of plumbing.
Fiancé/fiancée seems to me to be a different case; it’s the same word, just with different gender markings. You’d just need to take pains to make it clear that when you wrote “my fiancé,” you were really talking about a man, and not just making a usage error.
And the word “marriage” is a problem too. I don’t have a problem with the idea of gay marriage—in fact, I support it—but I think using the word “marriage” for anything that isn’t full, legal marriage only serves to confuse people. A few years back, when the Massachusetts Supreme Judicial Court was considering the issue of gay marriage, one of my neighbors thought it was ridiculous—not because he was opposed to gay marriage, but because two lesbians he knew when he was in college referred to each other as “my wife” and mentioned their “marriage ceremony” and he was sure they were legally married.
(Of course, now they can be.)