Shulchan Arukh, Orach Chayim 615

יום הכפורים אסור בתשמיש המטה. ובו ב סעיפים:יום הכפורים אסור בתשמיש המטה ואסור ליגע באשתו כאילו היא נדה וכן אסור לישן עם אשתו במטה:

“It is forbidden to have sexual intercourse on Yom Kippur” - Containing two paragraphs.It is forbidden to have sexual intercourse on Yom Kippur and it is forbidden to touch one’s wife113aThe following comment is given by Magen Avraham, (see footnote 33.): 615:1 - "His wife": It is forbidden (for him) to touch (her, his wife) also during the day (not only at night) and he should also not talk to her too much (Shenei Luḥot ha-Berit, של״ה, see footnote 20a.). And in the Maharil, מהרי״ל, (see footnote 8), the meaning is that one is to treat her (one's wife) according to all the laws of niddah (sexual impurity due to menstruation). as if she were in her menstrual period, and so it is forbidden to sleep with one’s wife in (the same) bed (even without intercourse).

הרואה קרי בליל יום הכפורים ידאג כל השנה ואם עלתה לו שנה מובטח לו שהוא בן העולם הבא:

One who sees a nightly pollution on the night of Yom Kippur, he should worry the whole year, but if a year has passed, he is assured that he will (have a place) in the world to come.