Kidushin4: 11
,,אִשָּׁה נָשָׂאתִי בִמְדִינַת הַיָּם הֲרֵי הִיא זוֹ, וְאֵלּוּ בָנֶיהָ” — מֵבִיא רְאָיָה עַל הָאִשָּׁה, וְאֵינוֹ צָרִיךְ לְהָבִיא רְאָיָה עַל הַבָּנִים.  ,,מֵתָה, וְאֵלּוּ בָנֶיהָ” — צָרִיךְ לְהָבִיא רְאָיָה עַל הָאִשָּׁה וְעַל הַבָּנִים.
[If one says:] “ I married a woman overseas; this is she and these are her children,” he must bring proof concerning the woman, but he need not bring proof concerning the children.  [If he says:] “ She died, and these are her children,” he must bring proof concerning the woman and the children.
Kidushin4: 12
לֹא יִתְיַחֵד אָדָם עִם שְׁתֵּי נָשִׁים, אֲבָל אִשָּׁה אַחַת מִתְיַחֶדֶת עִם שְׁנֵי אֲנָשִׁים. רַבִּי שִׁמְעוֹן אוֹמֵר: אַף אִישׁ אֶחָד מִתְיַחֵד עִם שְׁתֵּי נָשִׁים בִּזְמַן שֶׁאִשְׁתּוֹ עִמּוֹ. וְיָשֵׁן עִמָּהֶם בַּפֻּנְדְּקִי, מִפְּנֵי שֶׁאִשְׁתּוֹ מְשַׁמְּרַתּוּ.  מִתְיַחֵד אָדָם עִם אִמּוֹ וְעִם בִּתּוֹ, וְיָשֵׁן עִמָּהֶם בְּקֵרוּב בָּשָׂר. וְאִם הִגְדִּילוּ — זוֹ יְשֵׁנָה בִּכְסוּתָהּ וְזֶה יָשֵׁן בִּכְסוּתוֹ.
A man may not be alone with two women, but one woman may be alone with two men. R’ Shimon says: Even one man may be alone with two women when his wife is with him. He may sleep with them in an inn, because his wife watches him.  A man may be alone with his mother or with his daughter, and he may sleep with them with bodily contact. If they grew up, she sleeps in her clothes and he sleeps in his clothes.