Sullivan's Crossing newcomer Marcus Rosner knows he has his work cut out for him after that secret husband twist - but could Liam actually be a threat to Maggie and Cal? "Liam has a very complicated backstory and he's a ghost from Maggie's past. When the whole story is told, people will largely understand that this is a very relatable thing to have in one's life," Rosner exclusively told Us Weekly. "It is a very necessary thing to work through in order to get to your ultimate love story." Rosner reflected on the struggle of coming between a fan-favorite couple.