TT #663 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:05
When brothers dwell together and one of them dies and has no son, the wife of the dead shall not be outside to a strange man; her husband’s brother shall come upon her and take her to himself as a wife and perform the duty of a husband’s brother for her.
Torah Temimah points to Yevamot 39a.
TT lemma: וּלְקָחָהּ לוֹ לְאִשָּׁה.
וּלְקָחָהּ לוֹ לְאִשָּׁה – הֲרֵי הִיא כְּאִשְׁתּוֹ לְכָל דָּבָר, וּמְגָרְשָׁהּ בְּגֵט וּמַחֲזִירָהּ.
English: “And he shall take her to himself as a wife” — she becomes his wife in every respect; he divorces her with a get and may remarry her.
On the daf / in context: Once yibbum is performed, the relationship is that of a full marriage, not a continuing temporary bond.
Derash on the full marital status after yibbum.
After yibbum the woman is a full wife; subsequent divorce requires a get and remarriage is permitted.