Is it a red flag if a guy has kids that he is no longer in touch with?

I have been seeing a guy for a year. During the beginning, I asked him "why are you unmarried at your age 43?" I found it a bit unusual why a guy like his age would still be unmarried. He replied "I had always been working hard in school / career, never really had time to date. But recently, I didn't like the woman that my mom tried to set me up with"

But recently I checked his reddit profile history and I saw his posts from 6 years ago about a Valentine's day gift his "wife" had given him. My stomach turned so I asked him "are you married?" He replied "no. I"m divorced. why would you ask that?" I didn't reply.

Then I noticed another post from 5 years ago stating that his second son had been born and that he just brought his wife back from the hospital. I never told him that I found out that he had 2 sons. I doubt he would like me to confront him about this. But currently, I noticed that he never goes to see his children. He spends weekends with his parents and nephews. It really seems like his ex wife just disappeared with the kids.

I just felt really gutted about how he never told me he had been hiding this from me for so long. I'm also kinda found it off putting how he's no longer in touch with his kids.

Updates
+1 y
he says he divorced his ex wife because he wanted sex 2 to 3 times a day while she only wanted it once a day.
Is it a red flag if a guy has kids that he is no longer in touch with?
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