Sam never knows what to say when he talks like this. She can't say I love you; it's not that she doesn't, because it's Jack and she's always going to care about him more than she should. But he's different than the Jack she married and she's different than the Sam he fell in love with. She doesn't want him to love her for the person he remembers.

She doesn't know what to say, but she wants to acknowledge what he's said and let him know it means something to her. When she leans against him and rests her head against his shoulder, that's mostly why.