Is marriage without ketubah considered marriage, concubinage, or kiddushin she’einah re’uyah le’biah (marriage that cannot be consummated)? I have read a number of different things suggesting each of the three. In the discussion here about concubinage, it was suggested that concubinage=simply marriage without a ketubah, so marriage without a ketubah=concubinage. But I have also read that marriage may be contracted without a ketubah: either through biah or a ring. Finally, I have read one source suggesting that the couple may not have relations without a ketubah; thus, a marriage without a ketubah is a kiddushin she’einah re’uyah le’biah. Which is correct?
The presence or absence of a ketuba in an otherwise valid marriage has no effect on the validity of kiddushin. As such, it would be kiddushin she’einah re’uyah le’biah (marriage that cannot be consummated). The only reason such a marriage should not be consummated is a Tannaitic stringency of R' Meir in Ketubot (5th chapter). However, they are just as married without the ketuba.
Marriage as marriage, even absent a ketuba is different from concubinage. As a legal matter, no get is required for a concubine, and no ketuba either. As such, people say concubinage is like marriage without a ketuba, but that means no ketuba is needed, not that it is needed but absent. So having kiddushin & nisuin without a ketuba would not turn marriage into concubinage.