Do u think it's weird for a guy with a gf to be on a chat site and want to be friends with girls he doesn't even know?

So I'm on this chat site. It's kind of the same concept as tinder. But u can match with people and chat with them. But people also do sexual stuff with it too. But not me. But I swiped on this guy and messaged him. I said he was cute. And he said he has a gf and is just looking for friends. And he said that we could be friends. But I didn't feel comfortable with that cause it seemed weird since I didn't know him and he has a gf. He didn't think it was weird and when I told him that. He was like "well if u change your mind I'm here". But he didn't think anything was wrong with it. But if I had a bf I wouldn't really want him trying to be friends with girls online that he doesn't know and talk to them. I would rather him try to meet friends at school and stuff. Because he was pretty cute so it wasn't like he has no friends. I just thought it was strange. And I asked him if his gf knew he was on the app. And he said yes. But I don't believe him. Do u guys think it's weird or normal? And would u be ok with your bf or gf doing that? Ik I might be being paranoid and he has the right to make friends online. But I just thought it was strange in my opinion since he has a gf. Please comment what u think.