1 Corinthians 9:6

Or I only and Barnabas, have not we power to forbear working? (KJV)

Then: Paul continues presenting the list of distinguishing differences between himself and other apostles. Fee categorizes this as a third question with an answer that establishes Paul's authority as an apostle (p. 403). Paul seems to use Barnabas as another traveling apostle who worked and didn't travel in groups which would include wives. They had the right to and deserved monetary maintenance even if they didn't claim it (Baker, p. 131). By inference, if any one of the apostles mentioned in vs 4-6 was not an apostle deserving support, then neither was Paul; but if all the others were apostles deserving material support, then so did Paul deserve support. The means of support (that is, from a church) did not relate to the definition of "Who is an apostle?" On the contrary - because they were apostles, they deserved support. There is the possibility that additional members of traveling groups (wife, etc.) worked as they traveled place to place so that an apostle did not need to; however, as Barnabas and Paul traveled alone, they needed to do the work themselves.

Now: Some churches require their pastors to be married and expect compatible work from the wife. An odd problem for today's wives happens when (outside the Lord's will), the pastor divorces, yet is able to continue in another congregation as a minister. The wife is left without the husband and is no longer accepted as capable of doing the same tasks she did before - heads of women ministries, heads of children's work or valued for biblical knowledge. The issue is unseen and ignored.

Extra source: Cornerstone Biblical Commentary 1Corinthians (William Baker), 2 Corinthians (Ralph Martin & Carl Toney), ed. by Philip Comfort. Carol Stream: Tyndale House Publishers, c2006.
The First Epistle to the Corinthians by Gordon D. Fee (Eerdman's 1987) online athttp://books.google.com/books?id=XlBp10nUTXAC&dq=Gordon+Fee+Bible+commentator&printsec=frontcover&source=in&hl=en&ei=SwLNSu3nA4v6Mf2XlDo&sa=X&oi=book_result&ct=result&resnum=12#v=onepage&q=&f=false