Every relationship goes through rough patches. The hard part isn't recognizing conflict — it's recognizing when conflict has become the relationship's permanent weather instead of a passing storm. Most people who eventually break up spent months, sometimes years, quietly gathering evidence they didn't want to look at directly.
A few patterns tend to show up before people admit a relationship is over. You stop bringing up problems because you've decided they won't change anyway. You feel more like yourself around friends than around your partner. You've started imagining your future and quietly leaving them out of it, not on purpose, just by default. You notice you're relieved when plans get cancelled. You've stopped fighting for the relationship because fighting requires hope, and you've run low on it.
None of these signs is a verdict on their own — relationships ebb and flow, and everyone has weeks where they'd rather be alone. What matters is the pattern over time, not any single bad day. If you've been keeping a mental list like this for months, that list is itself the answer. The relationship isn't ending because of one dramatic event; it's ending because it already has, and you're just catching up to it.
The most honest thing you can do at this point is stop performing certainty you don't feel — for their sake as much as yours. A relationship that's quietly over deserves a real conversation, not another six months of both people pretending.