Why do some guys do this?

Ok so how normal is this or is he either just talking to me when he is bored or not interested….. so okay he starts a text convo and it could be going good then stops texting me Mid convo. I’m starting to sense he possibly has a girlfriend or dating someone on a serious note. This is weird odd to me. And no this is not a one time thing happens quite often. I’m probably gonna stop talking to him soon.
Why do some guys do this?
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