Perhaps he's wondering "why does she want to marry me so bad if we're so incompatible?". And maybe that scares him into thinking "this girl just wants to be married".
Or, perhaps he's pointing out your incompatibilities (even if they're totally minor) as a way to justify his feelings for this other person.
Either way, this is not what you want. Maybe if he said things to you, half as nice as he was saying to her, you'd show him your beautiful smile more often too
Time to cut your losses and move on.
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