What it usually means
Former partners are among the most frequent people in dreams, including years after the relationship ended and for people who are happily with someone else. That makes the first point the simplest: dreaming about an ex is not, on its own, evidence of still wanting them.
Dreams draw heavily on emotionally charged memory, and a relationship is one of the densest stores of feeling most people have. When something in your current life touches the same nerve — being ignored, being chosen, the same fight about the same thing — the dream reaches for the person who taught you that feeling first.
So the useful reading is less about who they are than about what they brought with them. The ex in a dream is usually a label on a feeling or a pattern. This is also why exes turn up at moments that have nothing to do with love: the nerve being touched is emotional, not romantic.
What changes the meaning
Getting back together. Often a wish for the feeling of that period rather than for the person: being younger, being wanted, being certain.
Arguing with them. An old conflict still running. Frequently the same argument you are now having with someone else, in a new costume.
Being ignored by them. Rejection replayed. May follow a recent moment of feeling overlooked, and not necessarily by anyone romantic.
Seeing them with someone new. Comparison and replacement, or simply confirmation that the chapter has closed.
Being glad to see them. Warmth toward a part of your past. It can be a quiet sign of having made peace with it.
An ex from long ago. The dream is less about them than about who you were then. What was going on in your life at that time is the better clue.
Dreaming of an ex while in a relationship. Very common, and more often about the present relationship than the past one — a similar dynamic, a similar stage, or a fear that it will end the same way.
An ex who hurt you. Here the dream may be processing rather than reminiscing. If such dreams are frequent and distressing, they are worth talking through with someone you trust rather than decoding alone.
Saying goodbye properly. The ending you did not get. People often report that after a dream like this the ex stops appearing.
When it keeps coming back
Repeated dreams of the same ex usually mean something from that relationship has not been put down: an ending that was abrupt, an apology never given, a question you still ask yourself. They are common after breakups without a clear end, and they tend to fade as the question loses its grip — not on a schedule, but not forever either.
They can also return when life rhymes with that time: a move, a new relationship reaching the same stage, an anniversary you had forgotten you remembered. Noticing what else is happening that week is often more useful than analysing the ex. The dream is dated by your life, not by theirs.
In Jungian terms
In Jung's terms, a partner carries a projection — the anima or animus, an inner image of the beloved that we first meet in someone else. When a relationship ends, the projection does not automatically come back with it. The ex goes on carrying qualities that were never entirely theirs.
Recurring ex dreams, read this way, are part of taking that image back. The question is not what they meant to you but what you gave them to hold — confidence, tenderness, recklessness, a sense of being at home — and whether you can hold it yourself now.
The plain form of the question is this. What feeling does this person stand for, and where else in your life has it just turned up.