Matthew Poole and continuators on John 4:18

18 For thou hast had five husbands, and he whom thou now hast, is not thy husband : in that saidst thou truly .

He tells her, that she had five Husbands, whether successively, the former being dead, and she marrying another: or five from whom she had been divorced for Adultery, is not agreed; the best modern Interpreters judg, that she had had five m[illegible: 1 letter]n, to whom she had been in Marriage, but so behaved her self toward them, that either for her Adultery, or some other froward behaviour towards them, they had given her a Bill of Divorce

and tho she now used, and lived with one as her Husband, yet in this she said truly, because her former Husbands yet living, he was not her Husband: This seemeth more properly the sense, than that after five legal Husbands death, she lived in whoredom with a sixth person. By this discovery, our Saviour both bringeth her to the sense of her sin, and also to an acknowledgment of him as the Messiah.