"after you have afflicted her": even after one act (of cohabitation).
(Devarim 21:15) "If there be to a man two wives": Scripture speaks of women in whom there is "being" (i.e., being as a wife) — to exclude a maidservant and a Canaanite woman, in whom there is no "being" (i.e., with whom marriage does not "take"). The implication is that excluded (from this halachah) are these (above) and those whom he has ravished or seduced, (where there is no "marriage"). It is, therefore, written "loved" and "hated." Is there such a thing as "loved" or "hated" before the L-rd (i.e., as affecting marital status)? It must be (that "hated," then,) refers to ravished or seduced (i.e., "hated" by the L-rd), not in the manner of all the wives (as opposed to "loved," connoting halachically permitted union, [the halachah of non-favoritism obtaining also with sons of rape or seduction]). Whence do we derive (for inclusion in this halachah) (the sons of) a widow (wed) to a high-priest and (the sons of) a divorcée or a chalutzah (a levirate-refused woman, wed) to a regular Cohein (even though these unions are halachically interdicted)? From (the repetition of) "hated" "hated." (I might think that only) these are included, these unions being forbidden by negative commandment (only); but I would not include unions liable to kareth (cutting-off) at the hands of heaven; it is, therefore, written, to negate this assumption, "hated" "hated." I might then think (that also included in the halachah of non-favoritism) are a maidservant and a Canaanite woman; it is, therefore, written "If there be to a man … and they bear to him sons" — Wherever there is "being" (see above), the sons are his (and the halachah of non-favoritism obtains) — excluding the above, where the sons are not (halachically) his, (but the mother's).