Have Parenting Questions? Ask a Parenting Counselor for Answers
You are right to be concerned. It may be "cold feet" or the realization that he will have to carry all the responsibilities of fatherhood or it may be anything else going on with him.
Couple's counseling may be very helpful as it will give the two of you a chance to have an objective person help you in sorting out your feelings.
Otherwise, you can only try to inquire from him as to what had led to this (he himself may not even know the answer to it) Try to find out how he feels about you, if anything had changed or if he just fees overwhelmed and confused.