For Sean Carlson, the little stories have added up the most. The moment that his mother, Barbara, said she had made "save the date" cards for Sean's upcoming wedding to another gay man, Jamie McGonnigal. The funny story of how Barbara and Jamie first met over a flat tire. The subtle, then matter-of-fact way that Barbara Carlson, a devout Catholic, let her son know she had moved past years of doubts and disagreements and was voting for the gay marriage amendment in Maryland last November. Barbara, 60, had put literature on that amendment in a place in her Hyattsvile, Md., home, so that Sean, 28, was sure to see it. It was her invitation for another talk in a progression of often stormy conversations over nearly seven years. Many had ended badly, including one where Sean stormed out of his mother's house and vowed never to return. So a conversation about that vote in Maryland, one of three gay marriage amendments that passed last fall, was not something he was looking forward to.