Three months in
is not nothing.

Skeptics say a monthiversary is an excuse invented by greeting-card copywriters. Maybe. But the three-month point specifically lines up with something real: it's roughly when the early rush of infatuation — the flood of novelty and dopamine that researchers call limerence or the "honeymoon phase" — starts to level off, and you're left looking at each other without the chemical fireworks doing the work for you.

That's not a downgrade. It's the point where a relationship gets tested on ordinary terms: whether the conversation still holds up on a quiet Tuesday, whether you've weathered a disagreement, whether you actually like this person and not just the feeling of being wanted by them. Plenty of dating advice treats "the three-month mark" as an informal checkpoint for exactly this reason — it's when couples often have the "what are we" conversation, because enough time has passed to have real data.

So the three-month anniversary isn't a fabricated milestone. It's a genuine inflection point that people mark with a date because it's easier to remember a date than to remember "sometime after the excitement wore off and it was still good."

Honestly — it's informal. "Monthiversary" is a portmanteau of month and anniversary, and you won't find it as a headword in most major dictionaries. It sits in the same category as words like "hangry" or "adulting": not yet fully official, but used constantly, understood instantly, and filling a gap in the language that nothing else quite fills.

That gap is real. English has a word for a yearly milestone (anniversary, from the Latin for "turning of the year") but nothing tidy for a monthly one. Couples, new parents counting a baby's age, and businesses tracking a launch date all reach for "monthiversary" for the same reason: the occasion needs a name, and this is the name that's stuck.

So the honest version of the claim is this: the word is informal slang, but the thing it names — a genuine, felt milestone at the month mark — is real. The website is right; the dictionary just hasn't caught up yet.