Marriage, Divorce, and Remarriage (2) (Matthew 19:10-15)

The disciples hear Christ teach about marriage and they figure out that Christ is pretty serious about the marriage commitment.  They ask the logical question: if marriage is so serious then why get marred?  It would seem to make more sense not to marry at all, but to remain single.  So, is it really better not to marry?  Is marriage only for the weak?  Is it sinful to be single?