Even without a polyamorous relationship angle, there's something that resonates about the comic. It's hard to expect one single person to fulfill every need you may have. Sure, it happens, but I imagine it's far more rare than we'd like to believe.
Yk that there's nothing wrong with polyamoury, it exists outside of Mormonism. The only problem with Mormon polyamoury is that it only allows men to have multiple partners, and the women aren't allowed to ask their husbands to be monogamous.