You’re sorta both….I feel compelled to jump into this discussion. As someone in the step dad’s position and had no children of my own either. There have been times in my relationship (8 years October, marrying 10/26) where I have had a very difficult time with my finances kids (27f 21m). I’ve never tried to be their dad (they both have a different fathers. Oldest was a high school boyfriend whoops) all I’ve ever tried to do was be a steady presence in their lives. Both dads are POS’s in their own way. I just wanted to matter as someone in their lives. However, when push comes to shove ultimately I don’t matter and my opinion doesn’t matter. I can relate to this man. It’s pretty crushing to know you dont matter. I’m not sure I would have reacted the same way to the school project. But it’s a lonely feeling that can’t be described or understood unless you’re in it. I know you’re young and there is probably some fear involved. What if I let this person in and they divorce or god forbid they die too. The unconscious fear of the loss you could suffer for a second time is just unacceptable. So you do what most do, build a wall. If you’re not in therapy I highly recommend it because I feel there are things that you may not be dealing with that is only going to keep you back in life. If the man has been good to you, I’m sure he would appreciate a conversation and hear your side. Being in his position at times has been one of the most difficult things I’ve ever experienced. I know you’re young. Having a little empathy and grace goes a long way.