Well, it never happened in my life. When I first met my wife, and when we first had sex, it was totally out of the blue, she was single, her fiance up and left her and we were just good friends. One day she showed up at my door and we had sex on the spot. I don't know what prompted it, and we never did talk about it, and we were married a long time.
I had sex with my wife's older sister (before we were married or dating), I walked with her to her friends place, and we got drunk, and smoked some weed, ended up at my room. I was doing the gentleman thing and was going to let her crash on my bed and I would sleep on the floor, only when I came back from the bathroom, she was in bed, covers pulled back and legs spread. Fucked her, never talked to her about it for the rest of our lives, though I did tell my future wife about sleeping with her sister before we got married (told her about everyone I ever slept with, so you know, no surprises)... I'll never forget that as my wife couldn't stop laughing at the thought of it. I slept with a childhood friend I grew up with, a random hookup when I was visiting relatives in town. No conversation about it to this day. I met a random woman on the street one night while sitting at a bus stop really late. went home with her for a coffee, ended up drinking booze and messing around with her. No conversation at all.
Maybe I am the exception to the rule, but I have just never had that happen. I see it far too much in visual novels and find it pointless. When I see them mention "I need to talk to her about what happened" and I am like, "WHY?!" LMAO... ah well. <shrug>