Snape's just being his Slytherin self at the end of the fic—taking what's offered to him on a platter, especially since any bad consequences would be suffered by Harry and not him. But he's hardly walking into happily ever after. What will things be like two months later? Three months? A year? In my mind, he and Harry will have to come to terms with a lot of things before moving forward, and not without Eileen and Ginny's help either. Alas, that's going to be a different story to tell ;)