Is dreaming about someone else cheating? No. I'll save you the scroll. You can't be unfaithful in a place you didn't choose to go, with a person your brain cast without consulting you, in a plot you'd have vetoed at the script stage.
But you did type the question, or someone typed it about you, and that's the interesting part. Nobody searches for whether dreaming about their teeth falling out counts as dental negligence. This one comes with guilt attached, so it's worth taking apart properly.
Cheating needs a choice. Strip infidelity down to its working parts and you get a decision, a secret, and an agreement being broken. A dream supplies none of them. You didn't decide anything, because the bit of you that makes decisions was off shift. There's no secret, because a secret is something you chose to keep. And no reasonable agreement between two people has ever included a clause covering what the other one's brain gets up to at four in the morning. If it did, we'd all be in breach.
A dream isn't a confession. The idea that dreams reveal what you really want is old, sticky, and far too flattering to dreams. A sleeping brain is a recycling plant. It takes the day's leftovers, a face from the office, a voice off the radio, an ex you haven't thought about in a decade, and bolts them together with no regard for taste. The casting is mostly arbitrary. The colleague who turned up in a starring role is there for the same reason the dream was set in your old school with a swimming pool where the canteen used to be. Availability, not desire.
The feeling is still real, though. This is where the tidy answer gets less tidy. You can know all of the above and still wake up feeling like you owe someone an apology. Emotion gets filed before the sceptic clocks in. There's research suggesting it runs the other way too: people who dream that their partner did something wrong tend to be a bit colder towards them the following day, over an offence that never happened. Which is absurd, and also completely human. The dream wasn't real. The mood it left behind is, and the mood is the thing that walks into the kitchen at breakfast.
You don't have to report it. A dream is weather. You're not obliged to announce it, and you're not hiding anything if you don't. If you do mention it, mention it as weather: odd night, strange cast, pass the milk. The trouble starts when either of you treats it as evidence. A dream produced in court is a terrible exhibit. The witness was unconscious and the footage has already degraded.
The same rule applies in reverse. If it's your partner who dreamed about someone else, or said a name in their sleep, the standard you'd want is the standard you owe. Judge people on what they do with their eyes open. Convicting someone on the output of their sleeping brain is how you end up arguing with a person about a film they didn't direct and can barely remember.
Here's the bit that does deserve attention. One dream is noise. The one that keeps coming back is a different animal, and so is the one you find yourself looking forward to. Still not cheating. But the useful question shifts. It stops being "what did I do?" and becomes "what am I going back for?" It might be attention you're not getting. It might be a version of yourself that only gets an outing after midnight. The other person in the dream is rarely the point. They're a borrowed face on something you're short of.
So the line, if you want one, isn't in the dream at all. It's in the morning. A dream about someone else is nothing. Going to bed early in the hope of a sequel is a small something. Rearranging your waking life around a person who exists only when you're asleep is, at the very least, a letter of intent.
A novel about this
I wrote a book that starts with this exact argument, and loses it. In The Soul Bank, Andy Clarke is a hardware consultant, a man who understands server architecture in forensic detail and his own head not at all. He lives with his girlfriend Kirsty, who believes firmly that dreams are a window onto what the soul really wants. One night, deep asleep, Andy says a name out loud. It isn't hers. It isn't anyone he knows.
He's baffled. She isn't interested in baffled. And then the dreams themselves turn up: vivid, intimate, relentless, about a woman he has never met, in a life that begins to feel more real than the one he's apparently living.
It's dark literary fiction with a speculative edge that never quite agrees to explain itself, and it takes the question in the title more seriously than I just did. Because "it was only a dream" is a solid defence right up until the dream is the best part of your day.
FAQ
Is dreaming about someone else cheating?
No. Cheating needs a decision, and a dream doesn't offer you one. You didn't pick the cast, the plot or the ending. What you do with the dream once you're awake is the only part that belongs to your relationship.
Why do I feel guilty after dreaming about someone else?
Because the feeling arrives before the sceptic does. Your brain files the emotion first and the label of fiction second, so you wake up with the guilt of something you never did. It usually fades within a day if you don't feed it.
Should I tell my partner I dreamed about someone else?
You don't owe anyone a report on your sleep. A dream isn't a secret, because a secret is something you chose. If you do mention it, mention it the way you'd mention odd weather, and don't offer it as evidence of anything.
What does it mean if my partner dreams about someone else?
Almost certainly less than it feels like. The dreaming brain casts from whatever is lying around: a colleague, an ex, a face from the telly. Judge a partner on what they do with their eyes open. You'd want the same standard applied to you.
Is there a novel about dreaming of someone else while in a relationship?
The Soul Bank is a dark literary novel that starts exactly there. Andy Clarke says a stranger's name in his sleep, and his girlfriend, who believes dreams show what the soul really wants, takes it as proof. Then the dreams themselves arrive, and they are harder to dismiss than either of them would like.