Marital problems are beyond our remit, unless Eric Schmidt's multi-billion-dollar shareholding in Google is at stake, and there's some thin business interest in the state of a marriage. But how the hell did Sand Hill Road's venture capitalists, like a sorority house on a coordinated menstrual cycle, enter mid-life crisis together? That's not meaningless gossip; it's a trend. We're hearing of four partners, well-known names, who've recently left their wives for younger women — in one case, at least, a Vegas 'realtor' with assets outside of property. In the obnoxious terminology of middle-aged men, they've bought themselves "upgrades". Why all at once? My theory: they all came to prominence in the late 1990s; they're in their forties now; and the renewed boom has given them all an injection of testosterone. Your guesses, in the comments.