He texts me late at night?

Anonymous
Im 21, he's 27. I'm a college student. He's a professor.
We met last year and were friends for 4 months, and then he tried to woo me for weeks. I rejected him, but we remained friends. We continued to text each other as friends, until last week he told me he already got a girlfriend (I didn't ask, he just told me out of blue). He said it like its news. I told him I'm happy for them and wished them all the best. But what bothers me is that ever since he told me that, he texts me only late at night (like midnight ffs). They weren't sexual though. Just friendly texts (how was ur day, what r u doing, go to sleep already, etc.). Maybe he's just really being friendly, but why text at that time?

Please state your opinions about this, guys and gals. I'm just confused. Am I overthinking?
Updates
+1 y
I forgot to tell, a friend confirmed that he really has a girlfriend, though.
He texts me late at night?
7 Opinion