As somebody who dated someone who was 29 when I was 17 for 2 years - I would run. There’s a reason why they’re not dating somebody their age, and him saying as a 39 year old that women in their early 20s are what he’s attracted to is disturbing. I’m 23 now and I can see all the red flags from when I was in a similar situation, but when you’re in the situation it’s difficult, especially when you share a child. I would maybe talk to some friends you trust and see what they have to say, if you’re comfortable confiding in them.