Why he not wants kids?

Don't discount his Words--he's not interested in getting married or having children, no matter how long he's dated a particular person or how he feels about that person. It doesn't matter what other people think of his idea; it's the right decision for him. If he feels strongly about it enough to let other people know, it's in his best interest to only be in relationships with people who share his viewpoint.

Don't believe you (or any other person) can change his mind about this, either now or several years from now. If you don't' share his views on marriage and children, it means that you and he are not compatible for a serious relationship.