YTA but just a tiny tiny bit. Like if 0 is 100% NTA and 100 is 100% YTA, you're probably at a 5 or 6. I'm gonna go against the grain and a bit and say that. So you asked not to be a part of their life at all if they tell them who their biological father was and that's perfectly fine. This request isn't asking you to babysit them or take them on vacations, they just want to meet for an hour or so and see who you are. After that you don't have to talk to them any more. It's such an easy thing to do to take a few hours and let them find out who they are and I think it would mean a lot to those kids. It's a far cry from meeting them for some coffee one time and "being a part of their life".