If I borrow an item from a friend and return it to his wife (not on his property) without notifying him first. Is it considered as though I returned it to the person himself, or am I still liable if it gets damaged before he himself gets it?
מתני׳ המדיר הנאה מחתנו והוא רוצה לתת לבתו מעות אומר לה הרי המעות האלו נתונין לך במתנה ובלבד שלא יהא לבעליך רשות בהן אלא מה שאת נושאת ונותנת בפיך
MISHNA: With regard to one who vows that benefit from him is forbidden to his son-in-law, but he nevertheless wishes to give his daughter, i.e., the wife of that same son-in-law, money, then, though he cannot do so directly, as anything acquired by a woman belongs to her husband, he should say to her: This money is hereby given to you as a gift, provided that your husband has no rights to it, but the gift includes only that which you pick up and place in your mouth.
Gemara Ibid. (through 88b):
גמ׳ אמר רב לא שנו אלא דאמר לה מה שאת נושאת ונותנת בפיך אבל אמר מה שתרצי עשי קנה יתהון בעל ושמואל אומר אפילו אמר מה שתרצי עשי לא קנה יתהון בעל מתקיף לה רבי זירא כמאן אזלא הא שמעתא דרב כרבי מאיר דאמר יד אשה כיד בעלה
GEMARA: Rav said that they taught this halakha only in a case where he actually said to her: That which you pick up and place in your mouth is yours. But if he said: Do as you please with the money, his stipulation is of no effect, and the husband acquires the money. And Shmuel says that even if he said: Do as you please with the money, the husband does not acquire it. Rabbi Zeira objects to this statement of Rav: In accordance with whose opinion among the tanna’im does Rav’s halakha correspond? It is in accordance with the opinion of Rabbi Meir, who said as a principle that the hand of a woman is like the hand of her husband. According to Rabbi Meir, a slave has no independent right of acquisition, and anything given to a slave belongs to his master even if it was stipulated otherwise (see Kiddushin 23b). Rav assumes that similarly, a married woman has no independent right of acquisition, but rather, anything that she attempts to acquire for herself is automatically acquired by her husband.
The Gemara subsequently poses a technical issue regarding a discussion in Eiruvin, which indicates that that which is given to a woman does not go to the husband. The Gemara ultimately answers:
אלא אמר רב אשי מתניתין בשיש לה חצר באותו מבוי עסקינן דמגו דזכיא לנפשה זכיא לאחריני
Rather, Rav Ashi said: In the mishna in Eiruvin, we are dealing with a woman who possesses a courtyard of her own in that alleyway, i.e., it is a case where the husband had earlier stipulated that she should have property of her own, to which he renounces all his rights. As, since she acquires the eiruv food for herself by virtue of the courtyard that she owns in that alleyway, she likewise acquires it for others.
In summary, therefore, according to Rebbi Meir, according to Rav, a woman acquires for her husband unless the gift was specifically given for her to his exclusion, or unless it was placed in property that she owns independently of her husband (יד אשה כיד בעלה). Shmuel holds that she never acquires on his behalf; as Rashi there explains, Shmuel does not hold of יד אשה כיד בעלה.
As we pasken like Shmuel by monetary matters (Rambam paskens like him in Nedarim 7:17 and Zechi’ah U’matanah 3:14), giving to the woman is not a valid way to give to the husband.
Even if one made the woman a messenger on your behalf (“this belongs to your husband; can you please give this to him for me?”), the item is still considered in your property, as she is your messenger (a messenger of a person is like him - Kiddushin 41a).
So, to directly answer your question, giving to her is not like giving to him.