Why would a guy who has a girl often text me?

It’s been happening for a while that we text in a bold way if u know what I mean but recently I found out his other account on instagram, and saw he had highlights of her , i go through his following to see the girl and check that she’s actually 20…maybe their relationship is complicated bc we are both 17 (we are on and off)

Updates
4 mo
I forgot to add also add they only have a highlight pic of Valentine’s Day
Why would a guy who has a girl often text me?
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