She has made it clear she is choosing her husband and family, and is making a concerted effort to avoid him. Yet when they run into each other and she starts to leave, he pulls her back in.
He is running for office, and if an opponent or the press were to see the two of them in a compromising situation, it would blow up Willow's life.
Yes, Willow is responsible for walking away regardless of what he says. But if he had any respect for her ... not to mention Michael and their kids, he would make a concerted effort to not be alone with her, and if they do run into each other not tell her to stay or give her longing glances.
Karen L.