Intermittent reinforcement is what happens when warmth arrives unpredictably instead of reliably. Because you can never tell which version of them you will get, you stay alert, keep trying, and treat every good moment as proof the relationship is worth it. The unpredictability is what binds you. “But sometimes it's wonderful” is not the exception to the pattern. It is the pattern working exactly as it works.
You have probably tried to explain this to someone and heard yourself sound unreasonable. You describe a stretch of coldness, or contempt, or silence, and then a night when they were funny and warm and completely present. The person listening hears the good night and asks what the problem is. The problem is that the good night is doing work. It is not a pause in the pattern. It is the part of the pattern that resets the count — taking a week of accumulated dread and dissolving it, so that when you sit down to add things up, you find you have nothing left to add.
Steady warmth is easy to leave. That sounds backwards, so sit with it for a second. When someone is reliably kind, you know what you have. You can weigh it, compare it, and walk away from it if you need to, because the memory of it holds a steady, unremarkable shape. Unpredictable warmth does not behave like that. When kindness arrives at random, you can never conclude that it is finished. Every cold week could be the one right before the good night. So you wait. And the waiting is not a weakness in you. It is the exact response the pattern is built to produce.
Think about the difference between a vending machine and a slot machine. If a vending machine takes your money and gives you nothing, you hit it once, swear at it, and never use it again. You learned fast because the machine was predictable and the predictability broke. A slot machine pays out sometimes, on no schedule you can learn, and people will sit at one for hours. Nothing about that is stupidity. A reward you cannot predict is the hardest kind to give up on, because no single failure proves anything. There is always a reason to try one more time.
Relationships run on the same wiring. When affection, approval, or plain ordinary decency arrives on a schedule you cannot learn, you start doing what anyone does at a slot machine. You keep feeding it. You build theories about what makes it pay out. You blame your own technique when it doesn't. This is why so many people describe becoming exhausting, obsessive versions of themselves — analyzing texts, replaying conversations, adjusting their tone and their clothes and their opinions. That was not neediness. That was you trying to find the pattern in something engineered not to have one.
The good moments are not evidence that it can work. They are the reason you can't leave.
Here is the part that makes people feel insane. If someone treated you badly and only badly, you would go. The attachment would starve. What happens instead is that the bad stretches raise the stakes, the good moments pay out against them, and the relief you feel when things are finally good is more intense than ordinary contentment could ever be. Relief is not the same thing as love, but in the body it can feel bigger and louder. Over time the contrast sharpens. The lows get lower, the highs feel higher by comparison, and you become more bonded to a relationship that is objectively getting worse.
The other cruelty is what this does to your baseline. Things that should be unremarkable — being spoken to kindly, being touched without an agenda, being believed, getting a straight answer to a straight question — become rationed. And when something ordinary is rationed, it stops feeling ordinary. It starts to feel like generosity. At some point you will catch yourself feeling genuinely grateful for a normal Tuesday. That gratitude is real, and it is also the most accurate measurement you have of how far the floor has dropped. It tells you something about the relationship, not about your standards.
You may already understand everything on this page and still feel unable to go. That is not a failure of insight. A bond formed through unpredictable reward is not stored in the part of you that reasons, so understanding the mechanism does not switch it off, any more than understanding how a slot machine works empties a casino. What understanding does give you is a second voice — one that can say, in the middle of a very good night, this is the part where I forget. That voice will not feel as loud as the pull. It does not have to be. It only has to be there.
Not always, and it does not have to be deliberate to work on you. Some people are genuinely unpredictable because their own moods are. Others learn quickly that rationing warmth produces compliance and keep doing it because it does. From the inside, the effect on your nervous system is identical either way. What matters for your decision is not what they intended but what living inside the pattern is costing you.
Every relationship has hard weeks. The difference is what the good times are for. In a steady relationship, repair follows conflict and leaves you feeling more settled, more yourself, more able to raise the next thing. Here, the good times function as relief from something the other person is causing, and afterward you feel less certain rather than more. Ask whether the highs restore you or simply reset your tolerance.
Because part of you is bracing. If warmth has reliably preceded a crash, your body treats warmth as a warning rather than a reward, even while another part of you reaches for it. That split is exhausting and it is not irrational. It is a fairly accurate read of the pattern. Many people describe this as the point where they stopped being able to enjoy anything in the relationship at all.