Maybe he brings it up when you start losing interest in him. Some men can lead a woman on for years with promises of marriage. It's alot like the way a woman can lead a man on with promises of sex, but never really put out. He probably knows it's something you want and he can milk it by talking about it and never actually doing anything.
If a man even chooses to get married these days, he chooses extremely wisely. Is the sex is any good? What will this woman look like in a few years? Can she cook? How are her cleaning skills? Does she have earning potential? Will she make a decent mother? Etc. No man will ever tell a woman this to her face. Divorce and child support laws in the West highly favor the woman. Women are rewarded for dumping the husband after children are born. She gets to be a mom; he gets to pay child support for decades. Not to mention, in many marriages, the sex becomes non-existent after the honeymoon, and the man is reduced to begging for it, or cheating.