I'd have to say Vahn, Kaede and Saendra are decent entries. I'd feel as if they settled down they'd be pretty good spouses for femSteele. Although, if my maleSteele somehow felt particularly guy-curious he wouldn't mind slipping a ring on a certain ausar mechanics finger and making him the happiest manwife ever.
My personal definition: someone who's most (or at least very) comfortable with assuming traditionally male roles in a relationship and who would make for a great partner and dad. Both Syri and Kiro qualify. Probably should have posted this in my OP.
Y'know when I see/hear "traditional male roles" in a porn 'verse it's usually just them being complete evil bastards on one hand or inconsiderate man-children on the other. Even if they have or had a supposed family they're mostly absentee husbands/fathers who's women assume all responsibilities AND STILL lovingly yearns for their mans return. AT BEST, I've seen some mainstream works where though the father isn't some sneering shitbag and a decent guy but he still abandons his responsibilities to do whatever the fuck he wants/needs to do. I call it "The Hoenheim Effect".
So yeah, a guy or gal WILLING to actually stay with and provide and protect for his family, that's more unorthodox if anything. I'd say it's telling that most of the good candidates on this list - other than the obvious not a lot of characters/development thing - are herms. Although, I don't see Kiro being good hubby material. Good wife? maybe. Good mother? Eeeeeeeeeeh. I see her as a hands off, distant parenting-type father.