How do I know if I really like him or if I only like him because he's unreachable?

For some reason I only seem to like people I can't have. But there's this one guy and since I met him I can't get in touch with anyone else, tho he already left my country and has (or had) a girlfriend. I'm just really fucked up because my mind might tricks me into thinking I like him.. I'm so confused, sorry if that doesn't make sense at all. Does someone know this feeling and can tell me their experience?
How do I know if I really like him or if I only like him because he's unreachable?
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