Siman 615
Presented here for study, not as a practical ruling. The Shulchan Aruch rules by Sephardi custom, the Rema's glosses by Ashkenazi custom, and the Kitzur follows Ashkenazi custom. For a practical question, ask your rabbi.
א יוֹם הַכִּפּוּרִים אָסוּר בְּתַשְׁמִישׁ הַמִּטָּה, וְאָסוּר לִגֹּעַ בְּאִשְׁתּוֹ כְּאִלּוּ הִיא נִדָּה; וְכֵן אָסוּר לִישַׁן עִם אִשְׁתּוֹ בְּמִטָּה.
1 Yom Kippur it is forbidden marital relations and in it is 2 paragraphs Yom Kippur it is forbidden in marital relations, and it is forbidden to touch his wife as if she is a niddah (menstruant) and similarly it is forbidden to sleep with his wife in (one) bed.
ב הָרוֹאֶה קֶרִי בְּלֵיל יוֹם הַכִּפּוּרִים יִדְאַג כָּל הַשָּׁנָה, וְאִם עָלְתָה לוֹ שָׁנָה מֻבְטָח לוֹ שֶׁהוּא בֶּן הָעוֹלָם הַבָּא.
2 One who sees a seminal emission on the night of Yom Kippur should be fearful all year, and if he lasts the year, he can be assured to him he is one who will get to be in the World to Come.