The tribulations of married life have been mined again and again in the theater. And this new musical, produced by Second City Theatricals, covers much of the same territory as plays like I Love You, You’re Perfect, Now Change. But Sex and the Second City is belly-laugh funny. Its sparse character development doesn’t even matter, and there’s enough of a plot to keep things moving along. In these finely honed sketches, directed by Ron West, the battleground of love is captured with sharp wit, as divorcing spouses (Katie Caussin and Brian Gallivan) try to make it through the obligatory couples couseling. Tina Gluschenko and Rob Janas play their lawyers and a slew of other characters, Janas with particular skill: he slides from straight Cubs fan to shallow gay guy so convincingly he doesn’t even look like the same person. Through 9/25: Thu-Fri 8 PM, Sat 3 and 8 PM. Northlight Theatre, North Shore Center for the Performing Arts, 9501 Skokie Blvd., Skokie, 847-673-6300. $20-$40. Closing.