Why a guy who was casually dating me, after the what are we talk (he dumped me) stopped using the dating app we had met on?

We had the define relationship talk (I initiated it, wanted to be exclusive) around 2 weeks ago and he said he's not read for anything serious (a few months ago he had ended his long-term relationship). During our casual dating period (2-3 months) he was actively checking the app (I could tell that from his whereabouts based on geolocation). After our talk he's not longer using the app (again I'm basing my assumption on geolocation), but he also hasn't contacted me since the talk. How should I interpret his behaviour?

Why a guy who was casually dating me, after the what are we talk (he dumped me) stopped using the dating app we had met on?
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