What was going on here?

This guy came onto me first seemed interested then one day for a little while 2 weeks over it that a little bit then he stopped talking to me left me on open mid conversation. I’ve been having a hard time with this. We haven’t talked and then I saw him last year in September he acted weird towards me but watched me talk to another guy. This other guy approached me & seemed interested in me very and the other guy just watched me talk so I don't know what that meant I’m just so confused still over this
What was going on here?
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