Kevin Systrom, 28, made off quite well when he sold his company Instagram to Facebook, personally clearing a reported $400 million, or $725,000 per day of work. But Systrom, described by one associate as an "ultra nerd," didn't get there on his own. Longtime girlfriend Nicole Schuetz has been with him the whole way.

Schuetz, who graduated Stanford at the same time as Systrom, is now back at the school as an MBA candidate; one person who knows her underlined her professional independence. In this, the couple resemble Facebook founder Mark Zuckerberg (27) and his longtime squeeze Priscilla Chan, a medical-school postdoc, Harvard grad, and sometime Facebook marketer, to say nothing of Facebook billionaire Dustin Moskovitz (also 27) and his girlfriend (last we checked) fiancée Cari Tuna, the Wall Street Journal reporter turned philanthropy president. (You can get a fuller rundown on Silicon Valley's most depressingly fortunate couples in our gallery here.)

Schuetz, who was involved in trading carbon credits and promoting conservation between her Stanford gigs, helps ground Systrom, who one associate described as being a very geeky, somewhat awkward guy through the early development of Instagram, before he began running in the past year with a cooler crowd of Bay Area notables like Digg founder Kevin Rose and TechCrunch writer turned venture capitalist MG Siegler. "His ego exploded as Instagram did," this person said, noting that Systrom took a much more visible role in the press and in speaking engagements than his more retiring co-founder Mike ("Mikey") Krieger (though Krieger did still manage to meet Michelle Obama and co-starred on some magazine covers).

Another associate said hanging out with Rose and company helped expand Systrom's long-present "fratty" side. Systrom's enthusiasms include, among other things, beer shopping, expensive whiskies, and lighting cocktails on fire.

Not that we object, and not that anyone's accused Systrom of being a jerk. The professional profiles of the co-founder — see especially TechCrunch's — make clear he's a focused, hard worker who plays well with others. Whether that remains true as Systrom enters the same rarefied, pretty young circles as Sean Parker remains to be seen. With his pre-money love still around to keep him grounded, he's at least got a fighting chance.

[Images via LeWeb11/Flickr, Kevin Systrom/Instagram, Kevin Systrom/Instagram, Nicole Schuetz/Facebook, Kevin Systrom/Instagram, josh/Instagram, Kevin Systrom/Facebook, Haute Living]