I would probably say from a woman's point of view, when he can so all the nasty human things people do, in front of you and you don't mind, when he isn't home in time and you get worried, when you think that you can live without him, then realize you don't want to. When you step back and see the stupid goofy things, and think they are the greatest. When you want to be with him all the time, even if he is on the toilet. When you accept the ugliest things about him, and sometimes even like them. When you want the best for them, and feel pity for them like when they have a bad day.

Most of all, when he or she gives you holds you and gives you all of their attention, you forget everything else in the world. Like it is only the 2 of you in the whole world. After years of being together.