Ask him if he still wants to go ahead with it or to wait and think about it. Marriage is a big step. People must feel ready for it, not coerced.
Wedding plans are things which the women tend to love doing and men just wish it was over.
It sounds to me like the guy thinks he has to marry you to "keep" you in his life. That is not a good reason to marry. It will be doomed to fail if that is the case.
