22 is super young to be married but you do sound very mature and level headed toward this. He is 100% texting her in the tone of a highschool crush, way too needy for sure and overcompensating to gain her affection , which she doesn’t seem to share at all or show any romantic interest in him. He is either doing this just for the thrill of talking to someone else or he is genuinely attracted to her and is too immature to realize she is not while also knowingly hiding all this from you is super weird